Instructions
Press the ̶0;Xbox" button on the center of your control and log in to your Xbox LIVE account. If your Xbox 360 is set to automatically log in after startup, a pop-up will appear, saying you've signed into Xbox LIVE, and you can skip to Step 2.
Use the left joystick to navigate to the ̶0;My Xbox̶1; heading and then press ̶0;A̶1; to select it.
Highlight ̶0;Change Gamertag̶1; with the left joystick and hit ̶0;A̶1; again.
Select ̶0;Add Points̶1; if your Xbox LIVE account does not have any Microsoft Points. To change your gamertag, you need to use Microsoft Points, purchased via credit card through your Xbox 360 console. The on-screen prompts let you select the quantity purchased and the credit used for purchase. If you have sufficient Microsoft Points under the ̶0;Balance̶1; heading, skip to Step 5.
Highlight ̶0;Enter New Gamertag̶1; and press ̶0;A.̶1; An on-screen keyboard will appear, or you can plug a USB keyboard into your Xbox 360 if you prefer.
Enter your desired multiplayer name and select ̶0;Yes, Use This Gamertag.̶1; Your account will be updated instantly, and all your Xbox LIVE achievements will transfer to the new name. When you play ̶0;Splinter Cell: Conviction,̶1; the new gamertag will appear as your multiplayer name.