How do I change my iCloud email account name? It still has my old account name on it

How do I change my iCloud email account name? It still has my old account name on it. I have since changed my Apple account name. For example my original email address was Fred@yahoo.com. Apple setup an iCloud account called Fred@icloud.com. Then I changed my email address and then my apple account to James@yahoo.com. However the icloud account still says Fred@icloud.com. I'm getting ready to do iTunes Match. Will this cause a problem? How do I change it? If I add a new email it will want to send a verification my the new account. Do I then need to setup an account with that on that?

Please assist!