This is for WiFi users only. Go into the Global Trade Station and put a pokemon (eg. Haunter, Kadabra, Graveler, Machoke) and put it up for trade. Don't worry about what pokemon you're getting because you are going to take it off anyway (But make it like a lv100 Piplup to be safe). Take it off, and it'll go through the standard trade screen. When you get it back it will show you the evolution screen and say "What? _______ is evolving!" This should work for all pokemon that evolve by trade, even ones that need hold items.