SAP Message 1X353 - Request &1 cannot be changed. Processing cancelled

Diagnosis
The piece list for request &V1& is to be completed, but the request isnot changeable.

System Response
The piece list cannot be completed. Processing is cancelled.

Procedure
Change the status of request &V1& to changeable. Run the programRS_STREE_OBJECTS_TO_REQ_GETagain.