Whenever you have to change the email address for your account, you will need to replace the previous email address with a new one from the Edit Profile tab on the My Account page. When you do this, the User Registration plugin will send an email confirmation to the new email address.
Please note that the change will be pending until you confirm the email sent to the new email address.
The email sent to the new address will have a confirmation link. Click on that link to confirm the change.