I asked the Apple Tech support people and their advice worked for me, it's a setting on the iPad itself. see below.
Follow the below instructions to sign in with your new account name.
1) From the home screen, tap Settings
2) Tap Store
3) Tap Sign Out
4) Tap Sign In
5) Enter your current account name "xxxx" and your password and tap OK.
If you are still unable to change the sign in name on your iPad, please sign into your account on your computer and then sync the iPad so the changes will be updated.