Trasformation

Is there a way without plugins to revert a trasformation skill effect? I mean, I've put in this skill a common event where the actor side view image changes with an other one. Now, how can I return to his previous image after some turns? (can't use troops event because that must be a skill that the actor can use in every fights)

I think you can set a common event with an parallel process. You can create a blank state (or show it if you prefer) that defines the actor is currently transformed. Then create a conditional branch:

-If Actor[id] is under state:
change graphics to the transformation
-else
change graphics back to normal

Remember to set a switch ON to trigger this common event.