Trade back a sinnoh pokemon to a player (need a GM)

[Bertomoreira]

Hello guys, we need your help urgently!

 

One friend who wanted to trade with me his kadabra to evolve to alakazam. So we did the normal trade and then I noticed i couldn't get it back to him cuz i didnt do sinnoh

So my question is, how could i return it back to him

 

 

Thanks in Advance

 

I don't know if a gm can help us to trade him back his poke... because i cant do nothing... tell me if need any type of account information if you can help us ty