Script to change sprite and animation

Hi, i'm trying to add some appearences to my character. I've juste modified the stylesheet by putting a colored filter with photoshop on it. Now i have my second spritesheet. I need a script to change the sprites of my characters. Only the colors changed so i think i can do a script which make the animator take the second spritesheet instead of the first one.

I thought about a solution : my stylesheet "DEFAULT"on which i programmed the animator could be renamed and the stylesheet "COLORED" could be renamed to "DEFAULT". It works manually but is there any command to rename a file during the game ? Or is there any other solution to do this ?

Thanks

PS : sorry for my bad english :)