Currently when you have a back to back order you are unable to change the quantity on either record. The only way to adjust the quantity is to delete the PO then adjust the SO and recreate the PO. This creates a new PO and now a discrepancy with the PO number that the Supplier has.
The request would be to allow either record to be updated and ideally keep the other in sync.
Jil Tansey
Seems like your using an older version but if not the PO qty can be changed provided it has not been received, invoiced, paid and closed. In the case of received, invoiced or paid, these records must be deleted to open the PO to allow for modification. In the case of closed PO, then you need to create a new PO