How do you switch Pokemon in mystery dungeon?

Answer 1

First, you have to beat the game. Once you beat it, the credits will roll up, but that does NOT mean that the game is over and you have to start the whole thing over if you want to keep playing. After the credits finish rolling, your Pokemon will want to stay in the Pokemon World. It will go back to the Pokemon World after that. Your partner will chat with you for a few seconds, then you will go to your Team Base. Once you wake up the next morning, come out of your Team Base, and your partner will be waiting. Your partner will explain how to switch the Pokemon you can control, and voila! You are a new Pokemon!