Change your preferences here.
Switches hold items with the target. This move does not work if the target has Sticky Hold or Multitype, or is Giratina-O, or if either Pokémon is holding Mail. This move works even if the user has no item, but will fail if the user or target has had an item Knocked Off.
If a Pokémon with a Choice Band, Choice Scarf, or Choice Specs is Tricked by / uses Trick on a Pokémon that does not have a Choice item itself, the Pokémon that has the Choice item after the Trick will be free to use whatever move it wants on the next turn only if it went first. That Pokémon will be free to select whichever move it likes regardless of whether it was originally the Pokémon with the Choice item. The Pokémon that moved second will always be locked into whatever move it used on the turn it was Tricked if it is the one holding the Choice item after the Trick. However, if both Pokémon are holding a Choice item, and either Pokémon uses Trick, then both Pokémon will be locked in to whatever move they used on the turn of the Trick(s).
For example, if Choice Scarf Jirachi is facing Choice Scarf Bronzong, and Jirachi uses Trick while Bronzong uses Stealth Rock, Jirachi will be stuck using Trick the next turn, and Bronzong will be stuck using Stealth Rock and therefore have virtually no reason to stay in, meaning Jirachi, if it decides to stay in, will have no choice but to attempt to Trick the Choice Scarf onto the incoming Pokémon. To expound on this, if the Bronzong user switches in Swampert to the Trick, Jirachi would be free to use whatever it wants. But if it uses Trick again and Swampert stays in to do whatever, then the next turn, Jirachi will be forced to use Trick, and not something like Reflect or U-turn.
Switcheroo is a Dark-type equivalent.