Editing Purchase Orders
You can change information on any incomplete active or blanket purchase order, and on all future and standing purchase orders. You can even delete a posted purchase order until you post receipts against it.
Multicurrency ledgers. If you use multicurrency accounting, you can change the tax group on a transaction until you add details, but only to another tax group that uses the vendor's currency.
What you can change after posting. After you post a purchase order, you can change everything you entered on the order except the purchase order number, vendor number, and completed detail lines.
You can add detail lines to a purchase order at any time, even after posting receipts for all the purchase order details and completing all detail lines. You can delete detail lines for which you have not received any items, and you can change the outstanding amounts of partially received details.
If you change quantities or delete purchase order details, quantities on purchase order are updated in Inventory Control.