Modding

I'm sure this has been asked many times before, but I couldn't find anything using the search function.
Basically, I need some help. How do you assign the attack animation of one creature to another?
Specifically, I need to change the attack animation of the Necromancer dragon (first upgrade, I don't remember what it's called in Russian) and give it the attack animation of the Elven dragon (similarly, the first upgrade).