Simplify the following text for a Grade 3 native English-speaking person.
Original: In PokÃ mon Diamond , Pearl and Platinum , another Trainer chooses the PokÃ mon with a type disadvantage to the player 's chosen PokÃ mon , but never battles the player ; instead , this character battles alongside the player as a tag partner in certain situations .
Simplified: It is also possible to trade PokÃ mon with a friend . The PokÃ mon in the battles never bleed or die ; they only faint .