Can you show a Example of script using the animator override controller?to substitution the original animation clip

Hello unity comunity, please someone know how to use animator override controler in Script, becausa i ant to creat a select character system,but i only want to change the animation.I see the documentation but i don´t understand how this work.

P.S:I´m using unity 5
Regards.

Roguelike tutorial briefly goes over animator overrides. https://unity3d.com/learn/tutorials/projects/2d-roguelike/enemy-animator-gm?playlist=17150

Dont know if that helps.