You have stage or animation with multiple frames, movie clips and graphics.
For an example we shall take the character from library Animated 3D Human Models
You need to change color of a skin of the character or color of clothes in all the document.
Make current anyone a frame of the document where there is a necessary element.
Press Ctrl+F or Edit > Find and Replace...
Choose parameters as in screenshot.
Choose the current color and new color.
Press the button [Replace All].
Color will exchange in all the document.
Replace other colors similarly.
Test the scene. (Ctrl+Enter)