Welcome to the forum.
I am not following. Do you mean that when you registered PrE, you created an Adobe Forum Account, and now want to change aspects of that?
If so, you should be able to click on your avatar, and go to your Profile. There, you can change the e-mail POP address, the screen name, the avatar, and also manage your e-mail subscriptions.
If this is the actual Adobe Account, you will need to contact Adobe. At the top of the forum pages, there is a link Contact, that will get you started.