1. Go to Mission Select and select a mission on Veteran. 2. After the first checkpoint, save & quit. 3. Go back to Mission Select and choose the SAME mission, however change the difficuty to Recruit. 4. While the level is loading, you will see a white bar at the bottom of your screen. When the bar reaches around about 33%, eject the disc or return to the Xbox Live Dashboard. 5. Reload the game and select Resume. 6. You should now be playing the level on Veteran with Recruit AI.