Default Skins - what will happen if I replace them?

Helloz,

At the moment I'm using a set of default skinz by LFB and I wants to try Evie's new skinz. What will happen to my sims that are using LFB's skins? Do they all appear like coal?

Thank you.

Not if you install the non-default versions of my skin, then you don't have to remove lady frontbums :)

And thanks to cece, I learned that if you end up with coal sims you simple pick a different skin-tone and then change their hair, then they should look okay :)