Dynamics GP Remove Completed Purchase Orders error "This document number already exists in history; it can't be moved."

A record exists in the history table that sohuld be deleted to allow the open PO t omove ot history correctly.

delete from pop30100 where PONUMBER = 'PO12345'
delete from POP30110 where PONUMBER = 'PO12345'

Re-run the Remove Completed Purchase Orders Routine