[Crash Ichimonji]

During the three-part Symbiot arc in the Spider-man animated series from the 90s there's a scene while Peter has the Symbiot suit (and finds nothing wrong with using it yet) and used it to change out his clothing appearance between the black spider suit, his normal attire, and more classy clothing (I think he at one point made his outfit into like a punk-rocker or something).

In the same Spider-Man series, Felicia Harding transforms back and forth between her more normal and preppy self to Black Cat numerous times.

Reboot does that in pretty much every episode when Bob, Dot, and Enzo (as well as Frisket and numerous binomes) with the namesake 'Reboot!' change the non-virus characters do to defeat the User in the games. Mostly it was costumes but it also did things like Bob and Dot becoming merfolk, Enzo into a zombie resembling Michael Jackson from Thriller, Andrea becoming a multi-armed Shiva-like warrior girl, and Bob, Dot, and Enzo as silvery robo-people in one game.