I hear you, Susan, and I want to help.

I’ve read your original post about wanting to apply the check payment to the Purchase Order (PO), but the payment record is under a different vendor’s name (the bank).

You're actually on the right track, converting your Purchase Order into a Bill. It's just that you've missed putting a check mark on the listed PO, as shown in the screenshot:

That way, your PO will be linked to the corresponding bill. Once done, delete or void the check payment entry that’s under the bank’s name. After that, record a bill payment against the created bill using the bank account you actually used, and select Check as the payment method.

I’ll ensure this conversation remains open for any future updates and discussions.