In instances where you want to track the change history or possibly need to supply your Vendor with an entirely new Purchase Order / PO # you can use the “Revise PO” button to duplicate the Purchase Order and mark through the old Purchase Order to show inactive. The PO # will be the same with a suffix of .1 added as shown below.
The PO will duplicate everything on the original PO so you can now make any necessary changes. See here for additional information.