At the mission selection screen, choose a mission on the Veteran difficulty. After the
first checkpoint, save the game, and quit. Go back to the mission selection screen, and
choose the same mission, but change the difficulty to Recruit. While the mission is
loading, you will see a white bar at the bottom of the screen. When the bar reaches
approximately 33%, eject the disc or go to the Xbox Live Dashboard. Then, reload the game,
and select "Resume". You should now be playing the mission on the Veteran difficulty, but
with Recruit AI.

When you reach a new Prestige rank, you will unlock a Gamerpic matching the Prestige
symbol. Reach the 10th Prestige to unlock the Sgt. Reznow Gamerpic.