I created and posted a purchase order to “Purchase Order” state in AX2009. Then I try to update purch line quantity of an item to 0. But I’m getting the standard AX error “Quantity cannot be reduced because the remaining update quantity changes sign.”
I guess, Packing slip or Inventory>Registration might have been done. Check the Inventory>Transactions for the POline, it must be “Ordered”, if so, you can change the quantities.