When people trade in the anime, they close by. Why can they just trade pokeballs.
Dawn (anime) takes the pokeball from Ash (anime) and she gives her "old" pokeball.
There's no need for a big machine to do it for them. Please help me! Thank you! :)
Note: Since I am a huge fan of Dawn, I will being using her in most (if not all) of my example. (If revalent.)