Hi there, greenerworldland.
The Pay From field is only used for tracking the transaction in QuickBooks' side. Though, the funds will still be taken out from your actual bank account that's enrolled for Direct Deposit.
If the transaction is still pending, you can void the vendor payment. Then, recreate and sent it again with the correct bank account in the Pay From field.
However, QuickBooks will not let us edit it if the payment is already processed. You will need to create a journal entry to transfer the expense from the incorrect bank account to the correct one.
Let me know if you have other questions.