What do you do to rebattle legendary Pokemon?

Question

I know you have to battle the Elite 4 to rebattle legendary Pokemon, but you have to physically beat them? Or can you just battle them and lose?

Comments

What game?

---

I guess any game but I'm currently playing HG (and maybe diamond)

Answer 1

You need to win against the Elite 4 if you want to rebattle legendary Pokémon. Once you beat the Elite 4, all KO'd legendary Pokémon not caught by you reset.
Source: Experience

Comments

Thanks!
(Also, is this the same for all games?)

---

Yes, it is, so don't worry!

---

Okay, thanks!