Need Action Replay Code to Change Rival's Starter! (Pokemon White 2)

[Trainer Gold]

So I used Pokegen to get myself an Ice-type Pokemon for a starter. But I had already chosed Oshawatt as a starter, meaning my rival had a Snivy. But I want him to have the Fire-Type as a starter! How can I change the rival's starter so he has the Fire Pokemon?

[ddhelmet]

Some save editors have the option to edit your "starter pokemon" so maybe if you change your starter to Snivy it can work. But I don't know if any of the gen 5 save editors have this function.