If you made the rankings in the Kanto x Alola Regional Rumble Online Competition, you can now claim your participation prize – a special code that can be redeemed for a Pidgeotite and a Steelixite now through April 30, 2017, at 23:59 UTC.
Just log in to the Pokémon Global Link (PGL) using the game that you used to participate in the Kanto x Alola Regional Rumble and click here. To redeem the code in your game, select Mystery Gift from the main menu, then select Receive Gift, and then select Get with Code/Password and follow the prompts to enter your special code. Be sure to enter the code in your Pokémon Sun or Pokémon Moon game before April 30, 2017, at 23:59 UTC.
Visit the Online Competitions page for Trainer and Pokémon rankings from the Kanto x Alola Regional Rumble.
Source: Pokémon Global Link