deleting old users email from iCloud

Several years when iCloud started I could only used an email I created @me.com for my iCloud account. My other computers I use use another email that is not @me.com. When I go to my mac book pro and try to delete my me.com account from computer so I can use my only email I used for iCloud the ➖ is greyed out so I can't delete the account. I want to get rid of the me.com account because causing confusion.

Any success with anyone accomplishing this?

Thanks

Patty