Hi Lyn
First of all, you cannot unpost a batch in AP, and it is very unlikely that such a feature will be added to Adagio.
Second of all, even if you could unpost a batch, coding an invoice to an improper GL account would not be a reason to do so. Once you retrieve the AP transactions into the GL, you can fix the error there, either before or after posting the retrieved AP batch.
Steve Schwartz