Changed admin user password and it doesn't work

Hello to peoples,

I don't want to log out of the computer. How do I reset my latest user admin password that doesn't work?

context:

I updated TODAY to Catalina, and wanted to change my password from when I had my logic board replaced.

I go into "Users & Groups". I change is the name of my computer from "XXXX's MacBook Pro" to something awesome. Then, I go to change the password. "Ah HA" I say to myself, the username is the same old XXXX (generic computer repair name). I successfully change the password. Then I realize that I want to change the username, too. So guess what? I click the lock to make changes and what happens? The flippin' password I just entered doesn't work.