In our system we have a PO (stock transfer) line item where there has been a a goods issue of 4 cases and a delivery for 4 cases. Those documents were posted in error and were actually one case short so a goods reciept for 3 cases was posted. The issue is now we have an old open PO for one case of this line item. Currently final delivery is checked in the delivery tab and we were told to simply click delivery complete but we get an error saying faulty lines and indicator cannot be set for this line item. How can we correct this using proper procedure?