How to change the base color of several objects at once while keeping the ratio the same?

[Micha5E6D]

Hello, I hope I am here in the right place. 

Imagine I have such a low poly object:

The objects all have about the same base color (dark blue/grey) but differ in brightness/darkness.

Is there a simple method to change the base color to another color, e.g. red?

By this I mean, how can I assign a red color to one of these triangles and automatically change all other areas according to this new base color. I want to keep the relation between the shapes, so if a shape A is darker than a shape B, the shape A should also get a darker red.

Thanks for helping!

[c.pfaffenbichler · Accepted solution]

Edit > Edit Colors > Recolor Artwork (edited)

or 

Edit > Edit Colors > Adjust Color Balance 

might be useful for this.