Just do a journal entry to correct the expense account.

You can do a zero dollar adjustment where you enter the invoice/vendor again in AP Data Entry, then select ADJUST.  Enter the incorrect GL account with a NEGATIVE amount, then the correct GL with the POSITIVE amount (this assumes the invoice was positive in the first place).  You just have to remember that in Invoice History Inquiry, these will be 2 separate entries, and the second can be seen by clicking on the right arrow after pulling up the original entry.

That worked perfectly.  Thank you for the help.