Once an Invoice is matched to a PO, there's no button that will allow you to undo it. It will be a bit of a process, but it's the only way right now to unlink them.
Please follow the below steps:
Download a copy of the Invoice and save to your desktop.
Delete the Invoice in Purchase Plus. From [Dashboard], go to [Documents] [Invoices], type the Invoice number in the Invoice search field and click on the blue 'magnifying' glass icon.
When the Invoice appears, click on the blue 'edit' box on the left-hand side of the state of Invoice column.
4. On the pop-up screen, click the red [Delete Invoice] button.
5. Resend the Invoice to the Marketboomer email address linked to your account.
6. Link the correct Purchase Order to the Invoice once it appears in your account and
process the Invoice as normal.
If your account is not set up for electronic invoicing, please process the Invoice as a manual Invoice.
If the Invoice is in a 'Cancelled' state, please open the invoice body, and click on the yellow [Reopen] button, as below, and follow the above steps to link the correct Purchase Order.
If the Invoice is currently 'Processing', please open the Invoice body and click on the yellow [Halt] button, as below, and follow the above steps to link the correct Purchase Order.