Things You'll Need
Instructions
Turn on the Xbox 360 and log your gamertag into Xbox LIVE.
Scroll to the "My Xbox" section from the dashboard.
Scroll one page to the right to find your gamertag details page and press "A." Gamertag options appear.
Choose "Change Gamertag" from the menu. A message appears informing you that changing your gamertag requires 800 Microsoft Points ($9.99).
Choose "Enter New Gamertag." An on-screen keyboard appears.
Enter your gamertag and press the "Start" button.
Select "Yes, Use This Gamertag" to confirm the change. Microsoft will deduct 800 Microsoft Points from your account.