To change your Bandai Namco ID email address, you'll need to first log in to your Bandai Namco ID.
From the accounts.bandainamcoent.com page, press "Log In" at the top right-hand corner of the screen.
On the following screen, press Log In under the Bandai Namco ID logo.
Enter your account credentials or choose an option at the top if you log in using another service.
Once on the Account Overview page, click on the "User Info" tab.
On the User Info tab, you are able to select "Change my Email on the Bandai Namco ID Site" located to the right of your current email address.
You'll be asked to authenticate your password one more time to continue.
On the Bandai Namco ID Account page, you'll find your current email address at the top. Press the "Set" button to the right and you'll be able to update your email address.