To change the email address that you initially registered with:
1 - Navigate to your profile
2 - Click on the Email
3 - Type in your new email then click confirm.
Note:
You will receive the email confirmation on the old email address, once you confirm the change, then your email will change to the new one.
You can find the email in the spam folder if you didn't receive it in your inbox.
Only the email changes and your password remains the same.