#1: Make sure 당신 have 2 3DSs, it doesn't matter if they're both yours 또는 if you're doing this with someone else. Make sure one has the Pokemon 당신 want to duplicate while the other has a Pokemon they won't mind getting rid of. Also make sure you're 프렌즈 또는 can trade in any way besides the Wonder Trade 또는 GTS.
#2: The 3DS with the crappy Pokemon starts the trade. 당신 trade the crappy Pokemon with the one you're duplicating. Proceed trade normally until 당신 both have the Pokemon.
#3: The screen now changes to a screen that says "Connecting, please wait...". The 3DS who now has the crappy Pokemon waits approximately 4 seconds, then turns off their 3DS. After a bit, on the other screen it will say there has been connecting problems. Make sure the screen is black and does not have an OK option, 또는 else it for sure did not work, but even if it does have a black screen, it still may not have worked.
#4: Repeat process until Pokemon is duplicate. Note the Pokemon that is not the one 당신 are duplicating will be gone, so make sure it's crappy 또는 something. Also, remember that this is a long, hard process. But also remember that when it does work, 당신 will be very happy!

So if 당신 like this please leave a 코멘트 and tell me which awesome Pokemon 당신 have been duplicating! Have fun doubling awesome Pokemon!

P.S. So far I have duplicated a Moltres and a Mesprit. Yes, a Mesprit. And awesomely French one.