Complex sentence: Wandmaker Ollivander tells Harry that two wands taken from Malfoy Manor belonged to Bellatrix and to Draco Malfoy, but Malfoy's has changed its allegiance to Harry.
Split into simpler sentences: Wandmaker Ollivander tells Harry that the two wands taken from Malfoy Manor belonged to Bellatrix and to Draco Malfoy. Ollivander also tells Harrry that Malfoy's WANs has changed its allegiance to Harry.