Is there any codes or way to edit the save to reactivate pokémon that just appear once and are gone when you catch them like the Legendary Birds and the Regi's in Platinum and Darkri, Shaymin, Acerus, Cresilia, Rotom, Regigigas, Gratina, Digalga, Pilkia, and the pixies
I want to reactivate them, expically the Regi's and the the Birds in my Platinum game.