Back in B/W and 4th Gen there was a little trick involving the GTS and trade evolutions not requiring one to actually trade and trade back the pokemon they wanted evolved.
Example: If you wanted a machoke to evolve, you could put it in the GTS for a terrible trade (Machoke for a lvl 100 buneary for example). Then you would reenter the GTS, trade for something, (trade random poke 1 for random poke 2 via search). After this you could take the machoke out, and it would evolve to Machamp.
My question now, does this method still work or is it a no-go in this gen? Sorry just got the game a couple days ago