Thank you for your response. I'm so sorry, I feel like this should be so simple but I can't seem to fix it as easily as the instructions make it. So I'm going to layout step by step what I am doing and seeing and you tell me where I am going wrong. 

Step 1: Edit Invoice - Change customer name on invoice to the correct customer

Step 2: Message pops up - The transaction you are editing is linked to others. Are you sure you want to modify? I Select Yes

Step 3:  I verify invoice is now showing under the correct customer

Step 4: I go back to the wrong customers account and the payment looks like this:

Step 5: When I select the payment to edit it and change the customer name I receive the following message:

Step 6: I select yes

Step 7: Then a screen appears with the amount received zero'd out:

Step 8: I'm not sure what to do from here and I'm scared i will make a mess of this, so I just exit out without saving the changes. Which then keeps the payment where it is at under the wrong customer.

I can see the invoice that needs to be credited. It's the first line item on the zero'd out screen. When I check the box for that line it applies the the amount in the "Amount to Credit" area as $-38,229.24 and the amount to apply area stays at $0.00. I don't want to select save and close because I don't want to mess this up further. Suggestions?

Thank you!