Chemlak |
Pathfinder Adventure Path, Lost Omens, Rulebook, Starfinder Roleplaying Game Subscriber
While it's not quite as clearly laid out as it tends to be in feats and class abilities, I agree with Volkard - the path ability sets a clear restriction on when you can select it again, and indicates that doing so adds to the legendary abilities of the existing item.
Having said that... ask your GM.
Game balance-wise, you're not upgrading the item to minor artifact, nor does any single item have more than 3 legendary abilities. Personally I'd probably allow it, especially since stealing one of the legendary items doesn't render the entire path ability useless to the PC.
Grin.