Instructions
Power on your Xbox console.
Select ̶0;My Xbox̶1; from the main menu.
Select ̶0;System Settings,̶1; and then select ̶0;Memory.̶1; Go to ̶0;Hard Drive,̶1; and then ̶0;Gamer Profiles.̶1;
Use the left analog stick to scroll through the list of Gamertags until you find the one you wish to delete. Select ̶0;Delete̶1; and follow the on-screen prompt to confirm that you wish to delete the Gamertag.