Change AppleID email address to a cancelled AppleID email address
Hi. I have two AppleIds. I want to change the email address of the AppleID that is linked to iTunes Store to the one that I use with iCloud. How can I do this?
If it's already being used as a primary email address on an account then you won't be able to change it to that address, all iTunes accounts have to have unique primary email addresses. You can either change the email address on your other account first so that you can then change it on the account that you are using with the store (if you don't have another email address that you can change it to then you can create a free email account via http://gmail.com or http://hotmail.com), or just change the store address to be something else.
You can change the primary email address on an account by logging into it via the Store > View Account menu option on your computer's iTunes, via the 'manage your apple id' button on http://appleid.apple.com, or by tapping on it in Settings > iTunes & App Store on an iOS device
Changing primary email address : Change your Apple ID - Apple Support
After changing it : What to do after you change your Apple ID email address or password - Apple Support