As far as I know, you can always remove an authenticator from your account, without having to supply any form of identification, etc., as long as you actually have the authenticator in your possession.
It is pretty much the exact same thing for the 'Mobile Authenticator' and the 'Dial-In Authenticator'. Each type of the official Blizzard Authenticators should have an original code listed somewhere that will always allow you to remove the authenticator from an account with, or a specific set of instructions you need to follow (such as calling Blizzard, texting Blizzard, etc.).