Email link

Have you tried doing an email address change? Note the restrictions in the article.

Apple ID Name Change.  * 

Make sure you turn off Find My Phone before signing out of the old ID. Once signed out and Find My Phone is off, then sign in with the new ID, then turn Find My Phone back on.

 What to do after you change your Apple ID or password - Apple Support  *  I suggest doing this before you change your Apple ID or password.

If you change the email address of your existing Apple ID you will retain access to all your data and prior purchases. You can also use a new email address for school and other places.