Instructions
Change Your Gamertag
The easiest way to retain your friends is to change your gamertag, if you have enough Microsoft Points to do so. Begin by selecting "My Xbox." Select your gamertag profile.
Select "Change gamertag." If you do not have enough Microsoft Points, the menu will ask you to "Add points." You need at least 800 points to change your name. Select a point package.
Enter your new gamertag. Select "Done." Your friends will automatically be transferred to your new account name.
Move Friends Manually
Turn on your Xbox. Select "My Xbox." Select "System settings."
Select "Memory." Select "All Devices." Select "Gamer profile."
Select your old gamertag profile. Write down all the names of your old friends. When you create your new gamertag, select "Add a friend" and enter each name down exactly as it appeared in your old file.