On saturdays, go to the card shop and choose passwordmachine. Beware, as losing your first duel with him will knock your rank down to Prince of Games.Subsequent duels with Sheppard will allow you to change your character's name after beating him. You'll now be able to duel with Chancellor Sheppard. Yu-Gi-Oh! GX: Duel Academy Cheats For Game Boy Advance Unlocking Chancellor Sheppard After achieving the rank of King of Games, a new room called Principal's Office will become available at the Duel Academy location.