diff --git a/vorgang-manager-interface/src/main/protobuf/vorgang.model.proto b/vorgang-manager-interface/src/main/protobuf/vorgang.model.proto
index 9b3cfb17e2a88c0fa29734d8edafe301d4cfa56d..479c9ead1e477c2aa7f07588a4df5b2ae02f08ff 100644
--- a/vorgang-manager-interface/src/main/protobuf/vorgang.model.proto
+++ b/vorgang-manager-interface/src/main/protobuf/vorgang.model.proto
@@ -214,18 +214,7 @@ message GrpcCreateCollaborationRequestData {
   string vorgangId = 1;
   int32 collaborationLevel = 2;
   reserved 3;
-  GrpcFachstelle zustaendigeStelle = 4;
-}
-
-message GrpcFachstelle {
-  string technicalId = 1;
-  string subjectId = 2;
-  GrpcFachstelleType type = 3;
-}
-
-enum GrpcFachstelleType{
-  ORGANISATIONS_EINHEIT = 0;
-  EXTERNE_FACHSTELLE = 1;
+  string organisationsEinheitId = 4;
 }
 
 message GrpcCreateCollaborationVorgangResponse {
diff --git a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CollaborationService.java b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CollaborationService.java
index 1a3e8b76dd1886a827db306de84b1262d52a2357..71742302527d0f51ffd2ac4205780dfef32996a2 100644
--- a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CollaborationService.java
+++ b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CollaborationService.java
@@ -59,7 +59,7 @@ public class CollaborationService {
 	VorgangHead getHeader(CreateCollaborationVorgangRequest request) {
 		return request.getVorgang().getHeader().toBuilder()
 				.collaborationLevel(request.getCollaborationLevel())
-				.organisationsEinheitId(request.getZustaendigeStelle().getSubjectId())
+				.organisationsEinheitId(request.getOrganisationsEinheitId())
 				.build();
 	}
 }
diff --git a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequest.java b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequest.java
index ed2b4675125567c326b8eab32f72ecbf78b973a9..a5fc2f862ab9333ca9ea6afb341908ad2c0691d7 100644
--- a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequest.java
+++ b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequest.java
@@ -33,5 +33,5 @@ public class CreateCollaborationVorgangRequest {
 
 	private Vorgang vorgang;
 	private int collaborationLevel;
-	private Fachstelle zustaendigeStelle;
+	private String organisationsEinheitId;
 }
diff --git a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapper.java b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapper.java
index e5674aa21c03e4f9d0154c3ab650e3a4831054fb..e7d98214f47767f8e504319062e735e1f1542162 100644
--- a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapper.java
+++ b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapper.java
@@ -29,7 +29,7 @@ import org.mapstruct.ReportingPolicy;
 
 import de.ozgcloud.vorgang.vorgang.GrpcCreateCollaborationRequestData;
 
-@Mapper(unmappedTargetPolicy = ReportingPolicy.WARN, uses = FachstelleMapper.class)
+@Mapper(unmappedTargetPolicy = ReportingPolicy.WARN)
 public interface CreateCollaborationVorgangRequestMapper {
 
 	@Mapping(target = "vorgang", ignore = true)
diff --git a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/Fachstelle.java b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/Fachstelle.java
deleted file mode 100644
index d472a536e7e4b1c384bebaac5d9af8ee3d461d58..0000000000000000000000000000000000000000
--- a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/Fachstelle.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package de.ozgcloud.vorgang.collaboration;
-
-import lombok.Builder;
-import lombok.EqualsAndHashCode;
-import lombok.Getter;
-
-@Builder
-@Getter
-@EqualsAndHashCode
-public class Fachstelle {
-
-	private String technicalId;
-	private String subjectId;
-	private FachstelleType type;
-
-	public enum FachstelleType {
-		EXTERNE_FACHSTELLE, ORGANISATIONS_EINHEIT;
-	}
-}
\ No newline at end of file
diff --git a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/FachstelleMapper.java b/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/FachstelleMapper.java
deleted file mode 100644
index b6d38bce42d6c65b4b65147159af5868931e36b2..0000000000000000000000000000000000000000
--- a/vorgang-manager-server/src/main/java/de/ozgcloud/vorgang/collaboration/FachstelleMapper.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package de.ozgcloud.vorgang.collaboration;
-
-import org.mapstruct.Mapper;
-import org.mapstruct.MappingConstants;
-import org.mapstruct.ReportingPolicy;
-import org.mapstruct.ValueMapping;
-
-import de.ozgcloud.vorgang.vorgang.GrpcFachstelle;
-
-@Mapper(unmappedTargetPolicy = ReportingPolicy.WARN)
-interface FachstelleMapper {
-
-	@ValueMapping(source = MappingConstants.ANY_REMAINING, target = MappingConstants.THROW_EXCEPTION)
-	Fachstelle fromGrpc(GrpcFachstelle fachstelle);
-}
diff --git a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CollaborationServiceTest.java b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CollaborationServiceTest.java
index 1f21a7720b4e4f94570ad3362332f4e02696f8b2..202002fb45f313d978d0f79bc0181a806deed13d 100644
--- a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CollaborationServiceTest.java
+++ b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CollaborationServiceTest.java
@@ -232,7 +232,7 @@ class CollaborationServiceTest {
 		void shouldSetOrganisationsEinheitId() {
 			var result = getHeader();
 
-			assertThat(result.getOrganisationsEinheitId()).isEqualTo(FachstelleTestFactory.SUBJECT_ID);
+			assertThat(result.getOrganisationsEinheitId()).isEqualTo(CreateCollaborationVorgangRequestTestFactory.ORGANISATIONSEINHEIT_ID);
 		}
 
 		@Test
diff --git a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapperTest.java b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapperTest.java
index 208327dbda34ec46c5a054873880206f1587e074..538564b81a70c301825e3125253829b10f88fcf4 100644
--- a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapperTest.java
+++ b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestMapperTest.java
@@ -24,36 +24,22 @@
 package de.ozgcloud.vorgang.collaboration;
 
 import static org.assertj.core.api.Assertions.*;
-import static org.mockito.ArgumentMatchers.*;
-import static org.mockito.Mockito.*;
 
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.mapstruct.factory.Mappers;
 import org.mockito.InjectMocks;
-import org.mockito.Mock;
 
 class CreateCollaborationVorgangRequestMapperTest {
 
 	@InjectMocks
 	private final CreateCollaborationVorgangRequestMapper mapper = Mappers.getMapper(CreateCollaborationVorgangRequestMapper.class);
 
-	@Mock
-	private FachstelleMapper fachstelleMapper;
-
 	@Nested
 	class TestMapFrom {
-		@Test
-		void shouldCallFachstelleMapper() {
-			mapper.mapFrom(GrpcCreateCollaborationRequestDataTestFactory.create());
-
-			verify(fachstelleMapper).fromGrpc(GrpcCreateCollaborationRequestDataTestFactory.FACHSTELLE);
-		}
 
 		@Test
 		void shouldMapFromGrpc() {
-			when(fachstelleMapper.fromGrpc(any())).thenReturn(FachstelleTestFactory.create());
-
 			var result = mapper.mapFrom(GrpcCreateCollaborationRequestDataTestFactory.create());
 
 			assertThat(result).usingRecursiveComparison().ignoringFields("vorgang").isEqualTo(CreateCollaborationVorgangRequestTestFactory.create());
diff --git a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestTestFactory.java b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestTestFactory.java
index e6c8f11d524a4f27b5e2d5ec55d3233450dfc6f7..5cb6d604bff8fc6f0762fa4fb33e3aee7afc313b 100644
--- a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestTestFactory.java
+++ b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/CreateCollaborationVorgangRequestTestFactory.java
@@ -23,12 +23,14 @@
  */
 package de.ozgcloud.vorgang.collaboration;
 
+import java.util.UUID;
+
 import de.ozgcloud.vorgang.collaboration.CreateCollaborationVorgangRequest.CreateCollaborationVorgangRequestBuilder;
 import de.ozgcloud.vorgang.vorgang.VorgangTestFactory;
 
 public class CreateCollaborationVorgangRequestTestFactory {
 
-	public static final Fachstelle ZUSTAENDIGE_STELLE = FachstelleTestFactory.create();
+	public static final String ORGANISATIONSEINHEIT_ID = UUID.randomUUID().toString();
 	public static final int COLLABORATION_LEVEL = 1;
 
 	public static CreateCollaborationVorgangRequest create() {
@@ -38,7 +40,7 @@ public class CreateCollaborationVorgangRequestTestFactory {
 	public static CreateCollaborationVorgangRequestBuilder createBuilder() {
 		return CreateCollaborationVorgangRequest.builder()
 				.vorgang(VorgangTestFactory.create())
-				.zustaendigeStelle(ZUSTAENDIGE_STELLE)
+				.organisationsEinheitId(ORGANISATIONSEINHEIT_ID)
 				.collaborationLevel(COLLABORATION_LEVEL);
 	}
 
diff --git a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/FachstelleMapperTest.java b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/FachstelleMapperTest.java
deleted file mode 100644
index 553ea10ddbff9eeab9669d1d518a66ea77fb0a28..0000000000000000000000000000000000000000
--- a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/FachstelleMapperTest.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package de.ozgcloud.vorgang.collaboration;
-
-import static org.assertj.core.api.Assertions.*;
-
-import org.junit.jupiter.api.Nested;
-import org.junit.jupiter.api.Test;
-import org.mapstruct.factory.Mappers;
-
-class FachstelleMapperTest {
-
-	private final FachstelleMapper mapper = Mappers.getMapper(FachstelleMapper.class);
-
-	@Nested
-	class TestFromGrpc {
-
-		@Test
-		void shouldMap() {
-			var fachstelle = mapper.fromGrpc(GrpcFachstelleTestFactory.create());
-
-			assertThat(fachstelle).isEqualTo(FachstelleTestFactory.create());
-		}
-	}
-}
diff --git a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/FachstelleTestFactory.java b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/FachstelleTestFactory.java
deleted file mode 100644
index d1ffaa975affb8289188982c9af5a84a5db00c88..0000000000000000000000000000000000000000
--- a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/FachstelleTestFactory.java
+++ /dev/null
@@ -1,24 +0,0 @@
-package de.ozgcloud.vorgang.collaboration;
-
-import java.util.UUID;
-
-import de.ozgcloud.vorgang.collaboration.Fachstelle.FachstelleBuilder;
-import de.ozgcloud.vorgang.collaboration.Fachstelle.FachstelleType;
-
-public class FachstelleTestFactory {
-
-	public static final FachstelleType TYPE = FachstelleType.ORGANISATIONS_EINHEIT;
-	public static final String SUBJECT_ID = UUID.randomUUID().toString();
-	public static final String TECHNICAL_ID = UUID.randomUUID().toString();
-
-	public static Fachstelle create() {
-		return createBuilder().build();
-	}
-
-	public static FachstelleBuilder createBuilder() {
-		return Fachstelle.builder()
-				.subjectId(SUBJECT_ID)
-				.technicalId(TECHNICAL_ID)
-				.type(TYPE);
-	}
-}
diff --git a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/GrpcCreateCollaborationRequestDataTestFactory.java b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/GrpcCreateCollaborationRequestDataTestFactory.java
index 367e272d41cd299caedd42bcf8b262a50495c837..adbccf0472dd286fd429d352a7afe01d98d70749 100644
--- a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/GrpcCreateCollaborationRequestDataTestFactory.java
+++ b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/GrpcCreateCollaborationRequestDataTestFactory.java
@@ -24,13 +24,10 @@
 package de.ozgcloud.vorgang.collaboration;
 
 import de.ozgcloud.vorgang.vorgang.GrpcCreateCollaborationRequestData;
-import de.ozgcloud.vorgang.vorgang.GrpcFachstelle;
 import de.ozgcloud.vorgang.vorgang.VorgangTestFactory;
 
 public class GrpcCreateCollaborationRequestDataTestFactory {
 
-	public static final GrpcFachstelle FACHSTELLE = GrpcFachstelleTestFactory.create();
-
 	public static GrpcCreateCollaborationRequestData create() {
 		return createBuilder().build();
 	}
@@ -38,7 +35,7 @@ public class GrpcCreateCollaborationRequestDataTestFactory {
 	public static GrpcCreateCollaborationRequestData.Builder createBuilder() {
 		return GrpcCreateCollaborationRequestData.newBuilder()
 				.setVorgangId(VorgangTestFactory.ID)
-				.setZustaendigeStelle(FACHSTELLE)
+				.setOrganisationsEinheitId(CreateCollaborationVorgangRequestTestFactory.ORGANISATIONSEINHEIT_ID)
 				.setCollaborationLevel(CreateCollaborationVorgangRequestTestFactory.COLLABORATION_LEVEL);
 	}
 }
diff --git a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/GrpcFachstelleTestFactory.java b/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/GrpcFachstelleTestFactory.java
deleted file mode 100644
index 4759c8c83e0f0e00283426c76fd203a214665bd6..0000000000000000000000000000000000000000
--- a/vorgang-manager-server/src/test/java/de/ozgcloud/vorgang/collaboration/GrpcFachstelleTestFactory.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package de.ozgcloud.vorgang.collaboration;
-
-import de.ozgcloud.vorgang.vorgang.GrpcFachstelle;
-import de.ozgcloud.vorgang.vorgang.GrpcFachstelleType;
-
-public class GrpcFachstelleTestFactory {
-
-	public static final GrpcFachstelleType TYPE = GrpcFachstelleType.valueOf(FachstelleTestFactory.TYPE.name());
-	public static final String SUBJECT_ID = FachstelleTestFactory.SUBJECT_ID;
-	public static final String TECHNICAL_ID = FachstelleTestFactory.TECHNICAL_ID;
-
-	public static GrpcFachstelle create() {
-		return createBuilder().build();
-	}
-
-	public static GrpcFachstelle.Builder createBuilder() {
-		return GrpcFachstelle.newBuilder()
-				.setSubjectId(SUBJECT_ID)
-				.setTechnicalId(TECHNICAL_ID)
-				.setType(TYPE);
-	}
-}