Things You'll Need
Instructions
Go to Ecruteak City. Walk east on Route 42 toward Mt. Mortar. Enter the cave and look for a trail of rocks that leads up the cliff wall.
Use Rock Climb on the trail of rocks to climb to the top of the cliff. Examine the Item Ball on the ledge to get the Dubious Disc.
Open the Pokemon team menu. Select "Porygon2" and select "Give." Select the "Dubious Disc."
Go to a Pokemon Center, such as the one in nearby Ecruteak City or Mahogany Town. Go upstairs.
Ask your friend to turn on his Nintendo DS and "Pokemon SoulSilver" game. Talk to the woman on the second floor to start a trade. Choose "Porygon2" as the Pokemon for the trade.
Have your friend confirm the trade from his Nintendo DS. When the Porygon2 holding the Dubious Disc transfers to your friend's game, it evolves into Porygon-Z. Ask your friend to trade Porygon-Z back to you when the evolution completes.