Locked documents in collaboration

I'm trying to organize contents in a C-room, and I cannot move folders because of locked documents. Some of these documents are locked by users who are no longer with the company, so I cannot go back to these users and ask them to check in the documents.

As an admin, is there a way for me to unlock a locked document in a collaboration room? Or delete a locked document?

Thanks for your help.

SRM Newbie