How to remove builds made by another player?

I have had a person help me edit some stuff but now some stuff of his is locked and i cant change it. hes already of my team and cant get him to do it. is there a work around or am i just stuck?

Have you tried anything via the creator portal, like remove team members or transfer project back to self ?

I havent treid transferring it to me. but i have removed him and it didnt work. he didnt check in his assets.

Can you revert to an older snapshot without losing too much ?