SAP Message 06648 - Requisition quantity already ordered in full (see follow-on docs.)

Diagnosis
You wish to change the required quantity in a purchase requisitionalthough this required quantity has already been ordered in full.
The changed quantity in the requisition is less than the quantityordered.

Procedure
INCLUDE NA_T160M LANGUAGE EN
If necessary, contact your Purchasing Department and have the orderquantity in the PO for this requisition changed.