It’s great to see you in the Community, pcorner.
Yes, you can reopen and then edit the amount paid on the invoice. The steps can easily be done with just a few clicks.
By following the resolution, the invoice will show the appropriate payment.
I’m also adding a link that lists all articles that will help manage customer transactions: QuickBooks Self-help.
Let me know in the comment box if you have any clarifications or other concerns. I’m here ready to answer them for you. Enjoy the rest of the day.