How to edit a Purchase Order after confirming

After confirming a PO, if you negotiate with the supplier again about the information on the PO, you can edit on the RMS by this function.

As in the above picture, you can edit some information about the PO like the Order Qty, Cost, Tax, or Discount. However, the editing would affect the MAC of a product if that product on the PO was received at least 1 qty. After editing the information related to that product, the system will show a popup like the below picture.