IN 'HARRY POTTER AND DEATHLY HALLOWS' HOW DID HARRY POTTER MASTER MALFOY WAND?

He disarmed him when they were in Malfoy Mansion

He lấy trộm, đánh cắp it from Malfoy, I believe, bởi overpowering him while poor Draco was in a state of shock because of the fallen chandelier. :)