As long as you don't have a different ressie booked for around the same time. I don't know if they do, but from what I read on the dis they might cancel both ressie's if you have two booked around the same time the same day. They don't want people double booking, understandably.
A fellow diser was able to help me out with a ressie and they just gave me their first and last name and confirmation number and I called tonight and easily change the name on it to mine. In turn, I was then able to give away the one that I had for that night that I didn't need anymore to a fellow diser and called up and did the same thing without a problem tonight.
I just said that our party had changed and that I would no longer be able to go but the other in my party was still going so I needed to change the ressie into their name. Both CM's said no problem.
Maybe I just got lucky two times in a row

but it worked for me
(edit: just wanted to mention neither of these were CC ressie's)
Hope this helps