you can't. trade with someone who has Pokemon white or use gts
use Pokemon GTS
get it in white, use poke transfer or trade with someone if u have it on ur pokedex or on GTS negotiations if not.
You can only get it in a trade from the GTS or, you can use the poketransfer and transfer it from another game
Duosion (and all evolutions/deevolution) can only be found in the wild in pokemon black. Use the Global Trading System (GTS) or a nice friend. If you want, i can post a solosis in the GTS in return for a gothita
You can use the GTS in Pokemon Platinum after you get the first gym badge from the Oreburgh City gym.
Mainly because a lot of people use Action Replay, Pokegen or Pokesav to make hacked pokemon.
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You can use the RageCandyBar in the Desert Resortto awaken Darmanitan in Pokemon Black and White.
totally
First, you have to have wi-fi(sold separately) Then go to the GTS and then talk to the attendant next to the door ten you can use gts
On the game when you complete it (defeat N, ect) you can go to route 15, theres a place there where 2 DS's can comunicate to trade.. BUT you can trade Pokemon from Pokemon Diamond, Ect Ect. Or you could just use GTS trade in the Pokemon centres. :) Hope i helped!