You want to make sure you keep the same AdobeID but associate it with a different email address.
If you get a new ID, your won't be able to read the books purchaced on the old one.
To change the email associated with the ID.
- Sign in at http://www.adobe.com/ using your old email and Adobe password.
- Goto the My Information under your name at the top right (or https://www.adobe.com/uk/account/account-information.html)
- Change the email under Adobe ID near the top left to your new email.
- You'll probably need to verify it by clicking on an email that will be sent to the new email.
(I can't quite remember the verification proces, but that's how they usually work).
Books are associated with the ID (remembered by an obsure code called a guid),
and the email address is also associated with the ID.
The book is not directly associated with the email address.
Some devices may still show your old email address as your AdobeID; but it should all work ok anyway.
