Changing the colors afterwards, I don't know how else to describe it.

Ok, so way back ago when I watched my first animate turotials on youtube, I saw that there is a function whre you can select a color and add it to a window. And when you use that color in you aniamtion and your done, you can afterwards simply change this color in the window and the color in the animtion will change as well. 

I wasn't able to find the tutorial so, I hope someone here knows what I am talking about.

Thanks in advance,

Cabbage