click on the edit profile link in the upper right hand corner.
replace the email address with something obviously faulty like bademail@goesnowhere.com
hide the email
Place your (player) name in the signature file (this will append all of the posts so new people can still see who played an old character after you have moved on)
Save all of this and you will be able to create a new account using the same email address (since the old account isn't using that address anymore).