His appearance has undergone a complete 'transformation'. [=his appearance has changed completely]
The building underwent various 'transformations' over the years.
the character's inner 'transformation'
(..) Vampire wouldn't tell. Cyborg wouldn't know. Shut up. Okay, if it's not any of those, I guess, um, we're looking at your basic... ...spirit guide transformation magic. That's kind of a biggie, actually. That is here. When the hero... - I guess that's... I guess, you. - Hm. (..)2009 17 Again
(..) Would you stop staring at me? - It's freaking me out. - It's freaking me out! I'm pubescent! Okay. So, uh... ...it's a classic transformation story. It appears in the literature time and time again. Were you at any point shot by a gamma ray? - No. (..)2009 17 Again