[ Ash nods his head. Sounds like Sokka gets the idea about how they work. ] I... dunno if ya have to destroy the Pokeball, but you can abandon a Pokemon or a Pokemon can leave its trainer and become wild again.

[ He gaze moved from Sokka to Snivy and Charizard as he says that, lingering for a minute before focusing on Sokka again. ]

Ya just put the Pokeball in a device and it teleports to the device you're transferring it to. And ya can't use more than six Pokemon at a time during official battles, like gym battles. But I mean, if you're runnin' some kinda farm you can have more than six Pokemon on the farm. And I guess you can have more than six Pokemon if they don't have Pokeballs or if they're not actually your Pokemon.