Q: alternate email address switch

You are not addressing Apple here. We are all just users like yourself

Can I update or change my Apple ID?

To manage your Apple ID, just sign in to My Apple ID at any time:

• Change your Apple ID email address to make sure it's one you use frequently.
• Change your password or security questions.
• Add a rescue email address to help you reset your security questions if you ever forget them.
• Add alternate email addresses to make it easier for others to communicate and share with you.
• Use the iTunes Store to update your billing information or check your purchase history.