The accounts created for the Hands-on Labs use your email address as the login name.
If you would like a different login name, you would need to register a new account with your new email address.
You can keep using your current account with the current ID and update your contact email address in your Profile under the Contact Information section, but your login ID will remain the same.
Aye, all of my contact details have been updated, but having my old company's email associated is a little annoying, but not too bad. Çest la Vie.