This site will allow you to:

You can NOT delete accounts or cluster memberships.

1. My MCS id is or will be my (currently active) AndrewID.
(This is most common.)

2. My CURRENT MCS ID is NOT my AndrewID,
OR my Andrew account is expired,
OR (1) doesn't work but I know my MCS password.

3. I am an external GUEST user creating a new account.
I registered with a link sent by a CMU user.