Pal Park

Pal Park is a building located within Route 221 of Sinnoh. In here, the process of transferring Pokémon from GBA games is possible. Once you've had them transferred, you can enter Pal Park and go through the various areas in order to re-capture the Pokémon. You can do this once per GBA game every 24 hours. You can earn various berries if you succeed in the process