The only way to get Porygon2 is by trading a porygon that is holding the item UP-Grade.
It is impossible to obtain a Porygon2 without trading. You can get a Porygon and trade it with an Up-Grade or you can get a Porygon2 from the GTS but there is no way to get Porygon2 without trading.
you have to link trade porygon
you have to have a upgrade and then trade it
It evolves porygon2 (trade)
It evolves Porygon to Porygon2 when traded.
In Pokemon platinum there is an ace trainer at the begining of route 216 he has a porygon2 at level 40 and two others
you give it to porygon and trade it and it evolves into porygon2
Give Porygon an upgrade to hold and then trade it. Also, if you want a Porygon-Z give Porygon2 a Dubious disc to hold and then trade it.
A dubious disc is a hold item for Porygon2. If you trade a Porygon2 that's holding a dubious disc, it will evolve into Porygon-Z.
In poke platinum you get a black poke flute from Looker the agent
Not one hundered percent sure but i think its the one that evolves porygon in porygon2 OR its the item that evolves porygon2 into porygon-Z
Porygon2 evolves with trading, while holding a Dubious Disc. This item can be found in Route 225 and the Team Galactic HQ in Veilstone City.