Here Is A Way It Is Called The [***Masuda Method***.]
Or You Could Use Hacks And Cheats To Do It Too.
If You Are Trying To Make An Un-Shiny Poke'mon Shiny,
Use Hacks. It Will Not Be Cool That Way Since You Bacicly
Hope I Helped U! :)
Except for Action Replay / Hacks, Absolutely NOT!!!!
You can hatch and catch Shiny Pokemon, but you can't make Pokemon you already have Shiny.
Yes, you can Modify pokemon to make them shiny but that isn't a good idea. it takes out the fun of everything