diff --git a/proto/caosdb/acm/v1alpha1/main.proto b/proto/caosdb/acm/v1alpha1/main.proto
index 545c4084324b062d49066aa513585041eddc2b0f..b5bb1ae04497e4cfb1dfe85c11e540e89a7e3c12 100644
--- a/proto/caosdb/acm/v1alpha1/main.proto
+++ b/proto/caosdb/acm/v1alpha1/main.proto
@@ -111,15 +111,25 @@ message RetrieveSingleRoleRequest {
 message RetrieveSingleRoleResponse {
   // The role.
   Role role = 1;
+  // Known users with this role
+  repeated User users = 2;
 }
 
-// Request message for the <+TODO+> RPC
-message UpdateSingleRoleRequest {}
-// Response message for the <+TODO+> RPC
+// Request message for the UpdateSingleRole RPC
+message UpdateSingleRoleRequest {
+  // The role
+  Role role = 1;
+}
+// Response message for the UpdateSingleRole RPC
 message UpdateSingleRoleResponse {}
-// Request message for the <+TODO+> RPC
-message DeleteSingleRoleRequest {}
-// Response message for the <+TODO+> RPC
+
+// Request message for the DeleteSingleRole RPC
+message DeleteSingleRoleRequest {
+  // the name of the role.
+  string name = 1;
+}
+
+// Response message for the DeleteSingleRole RPC
 message DeleteSingleRoleResponse {}
 
 ///////////////////////////////////////////
@@ -195,13 +205,26 @@ message RetrieveSingleUserResponse {
   User user = 1;
 }
 
-// Request message for the <+TODO+> RPC
-message UpdateSingleUserRequest {}
-// Response message for the <+TODO+> RPC
+// Request message for the UpdateSingleUser RPC
+message UpdateSingleUserRequest {
+  // The new user.
+  User user = 1;
+  // The new password. Password will not be updated when this is empty.
+  string password = 2;
+}
+
+// Response message for the UpdateSingleUser RPC
 message UpdateSingleUserResponse {}
-// Request message for the <+TODO+> RPC
-message DeleteSingleUserRequest {}
-// Response message for the <+TODO+> RPC
+
+// Request message for the DeleteSingleUser RPC
+message DeleteSingleUserRequest {
+  // The user's realm
+  string realm = 1;
+  // The user's name
+  string name = 2;
+}
+
+// Response message for the DeleteSingleUser RPC
 message DeleteSingleUserResponse {}
 
 ///////////////////////////////////////////