Need to allow supplier site change on incomplete PO when PO references BPA

Summary:

We had a personalization on the PO header site field to allow the user to change the supplier site on a PO in "incomplete" status that stopped working after 23A. This was used by multiple healthcare customers who are now having to spend a lot of extra manual effort recreating POs.

Content (required):

We are using BPAs and have the "Allow ordering from unassigned sites" box checked on the controls tab. We need to be able to choose a different supplier site on an incomplete PO. For example a user creates a PO that is CMK/EDI enabled, but it's a rush order so the users need to change the site to a non CMK/EDI site in order to get the product delivered quicker.