Yeah, I know there's a big potential to look dumb on this one, but can I restart a certain playthrough? I'm playing through with my favorite char, my Maya. I beat UVHM with her already, and just want to go through the story again.
At the main screen, load your toon and where you would normally pick which mode you want, normal tvhm or uvhm. There is a prompt to reset uvhm. I think it's square --- "Did you just say laser-butts?" "I don't know what that is, but I want it!"