diff --git a/modeler/src/views/decision/designer/api.ts b/modeler/src/views/decision/designer/api.ts
index e05404e..16fdd21 100644
--- a/modeler/src/views/decision/designer/api.ts
+++ b/modeler/src/views/decision/designer/api.ts
@@ -28,6 +28,10 @@ export const findOneTreeByPlatformId = (platformId: number): Promise<BehaviorTre
   return req.get(`/system/behaviortree/platform/${platformId}`);
 };
 
+export const findSubPlatforms = (treeId: number): Promise<BehaviorTreeDetailsResponse> => {
+  return req.get(`/system/behaviortree/underling/${treeId}`);
+};
+
 export const findOneTreeById = (id: number): Promise<BehaviorTreeDetailsResponse> => {
   return req.get(`/system/behaviortree/${id}`);
 };