Good morning and welcome to SA! If you already have an alternate email address set up, you can PM the Admin who can change your registration information. However, the email address that you use to register here is only used for this site. When you enter sweeps, you need to click in to each one separately to enter it. You do not need to use the same email address that you used to register on SA.
This can all be a bit overwhelming at first. Please continue to ask questions and we'll do our best to answer them. Happy sweeping!