I did found my answer on this board but I will say it again anyway.
Beat the game, go talk to the professor and receive the TMV pass. In Kiloude City go in the battle Mansion and win at least 1 round. Then in Kiloude City go north and you will find you rival, beat him. He will then ask you to go talk to the professor in Anistar city in front of the huge Crystal.
After this between 8 and 9 pm you will find glittery purple in some locations http://www.serebii.net/xy/megaevolutions.shtml --- Your every movement is in vain. Your very existence is a triviality.-Jedah
Do one battle masion battle then go to the top of kiloude the benchpark your rival ahould be there beat him then he says where prof scayamore is and scayamore gives you da upgrade sorry im tired and typing on my mobile.... --- Friend code 3DS (PM me if you added me) = 2879-0303-7697 Animal Crossing New Leaf Dream Suite Address Code: 6100-2474-3220 town=Holland/Player name=13ruce!=D=P