Workflow issues with Invoices matched to wrong PO then corrected to correct PO

Summary:

Invoice was initially matched to PO. The invoice approval was routed to a person who realized that it was not the correct PO and rejected the invoice approval. The invoice was then matched correctly to PO which should of routed to another approver but instead it routed to the approver of the incorrect po again.  Unless he approves it the workflow is not moving to the correct approver. The only workaround we have found is to cancel the invoice and manually enter with a correct PO. Is there some adjustment we can make so that we don't have to delete