Trading Pokemon

Anyone who has ever played Pokemon knows that trading is a huge part of the game, especially for those who require trades to evolve.

Is there a way to trade (for evolution purposes) Pokemon be it through a hack or a cheat with a single Gameshell? Does anyone know if this is possible/have a tutorial on how to go about doing it?

Any and all help would be appreciated!

Gameshark chests are your best bet for a single system. And I find cheats only work on MGBA.