Topic: Pokemon Diamond Question

My son has been bugging me for a Pokemon game. I had him borrow a friends to see if he really likes it before spending the money. He is simply continuing a game already in progress. My question is...how do you switch out Pokemons already in the Pokeballs. His friend has 493 captured Pokemons and he want to try different ones in battle.
Any thoughts?

Go to a Pokemon Center, and use the computer to access Bill's PC, then choose "move Pokemon" to switch out your team with those in storage.

Perfect...thanks.

Can you only have one save game file on Pokemon games?

Unfortunately yes due to the rather large size of the files

Ok...thanks.