Instructions
Enter "Xbox Live" to go online. You can also manipulate your callsign in "Split Screen" if you want to play with other players on one console.
Choose the "Callsigns &Killstreaks" option.
Select "Title" to change your title. A screen will appear with some titles visible and others will have a lock symbol in front of them. This signifies you have not unlocked the title yet.
Use the trigger buttons to scroll through the pages of titles and find the one you want. Press "A" to select a title and it will appear on your callsign at the top of the screen.
Press "B" to exit the screen. Select the "Emblem" option at the "Callsigns &Killstreaks" menu. Scroll through the emblems and select the one you want with the "A" button to finish customizing your callsign.