This question already has an answer here:
In the Half-Blood Prince, Draco Malfoy gained ownership of the Elder wand by disarming Dumbldore when he was holding the Elder wand.
Could someone have used Expelliarmus on Harry to take ownership of the wand, even if he didn’t have it on him? Because Draco Malfoy had ownership, and then Harry got ownership by stealing Draco's normal (original) wand.
Sorry if this is confusing.