I have an expense that was recorded in May that was a Q1 bill, How do I move the expense into the previous months?

edit the bill and back date it.  thought there is the school o thought that when you get the bill that is the date of expense

If you posted this from the bank feed because you paid the bill in May, then open the Expense transaction that was created and change the allocation to Accounts Payable.  Then create a Bill dated on the correct date, and use the same expense account you used in the payment. That zeroes out AP