To easily evolve Pokemon that can only be evolved by trading is to use the Global Trade Station . Fly to Jubilife City, and go to the Global Trade Station. Talk to the woman at the counter, save the game, and enter. Select "Deposit", then deposit the Pokemon that you wish to evolve. Request a Pokemon that is great such as level 100 female Piplups. Seek a desired Pokemon. Once you have found any Pokemon that you can trade for, trade it. After you have successfully made a trade, go to "Summary", and take back your Pokemon. As soon as they come back, they will evolve, just like when someone trades them to you. This trick will work on all Pokemon that evolves by trades.