Sorry but we can only change the username, what you can do with the email is to release the license associated with your account so you will be able to register a new account with a new email, and register your license back to that newly created account.
1) To do this navigate to your licenses page.
2) Unlock your license (the padlock icon).
3) Register a new account here using the license that you just freed up with the desired username and email.
4) Then use that new account to assign your license to your site URL.
Setup - Product Validation