We prefer that you simply sign up for a new account under a different username :-) Since we don't ask for email addresses during registration (intentionally), it's tricky to reset the password if you have lost the existing one.
If you still would like to reuse the current username, please send me a private email with your username. I will remove your account so that you can register another one under the same username.
(Note that we trust our users not to send someone else's username... otherwise, we have to immediately suspend this manual process if it happens once.) Let me know if this sounds good to you, and hope this explanation can serve as a reference in the future.
Best,
Francis