How do I change a PO on an Invoice?

Invoice header details such as PO number can only be edited on invoices that have been Quarantined by the system or rejected by your customer.  If an invoice is not Quarantined or Rejected and require a change to the PO number, you should contact the customer asking them to reject the invoice.

A PO can be changed on a Quarantined invoices by logging in to OnePosting, choosing 'Customers' on the top left, and choosing 'Quarantined' (or 'Rejected' if the invoice is rejected) from the outbound menu.

Then select the Modify Header option next to your invoice, and click submit.  This will remove it from the Rejected or Quarantined view and send it to your customer.