put it on GTS and ask for a LV 100 Mew then take it back off and it will evolve. from what i heard if you put a Poke on GTS then take it back off it evolves.
then you put it on GTS and it comes back it fools the game into thinking it was traded and it evolves. if you ask for something ridiculous you won't get your pokemon taken and if you do you'll get something better back.ill help and do not put it on gts all u need is to trade it