You do not need to go through the myAT&T for Business registration process again.
To add another account to your myAT&T account:
- Sign in to your myAT&T for Business with your current User ID and password.
- Select VIEW PROFILE, found in the top navigation area.
- Select the Add an Account link.
- Enter your new information and select Submit.
An online registration code is required to Add a new account. You will have an opportunity to request the online registration code once you have clicked the Add an Account link.