Can you skip the credits in Pokémon X and Y?
Just reset the game.The game saves when it puts you in the hall of fame. I forget if it tells you exactly when it saves, but if developers names are scrolling along the screen it's safe to reset.
Per Ivo Beckers' comment it might not be safe to do this the first time since it's a bit different--but if you're just farming the elite four after winning once you can reset freely.