How do you change skin color

you would need to load another material for the figure.

The question is quite general and can have multiple answers, depending on the render engine being used and the arrangement of material room shader nodes. RedPhantom suggested using a different skin texture for the figure. However, it's important to know which figure you are using and what content you have. To provide the best help, we need more information about your intentions and your experience with Poser.

And without editing, you may play with what's in the material room:

If you're using the PoserSurface node: change the white (example above using the Alternate diffuse of an EZSkin setting)
If you're using Cycles: add a Cycles > Color > Mix node and play with the fac, while setting the blend type to mix. Other blend types may have fun effects as well.
Same with the PhysicalSurface node:

And using Richard60's Color ramp, you may have even more fun... 

Nice presentation, Y-Phil, but this individual's skill set is questionable due to his recent sign into Renderosity.  He might be a newbie or a spammer.

THANK YOU Every ONE!

You are all very kind to take so much time to help me.  I did not realize how much time you have to put into poser.   A couple of  days Ago I spent 3 hours trying to do simple things.   I gave up, and got Daz 3d studio after one hour I can a add a figure clothes and background and pose.   Again thank you all so much!

I hope I am not offending anyone

Nick

That's weird, but ok. Not sure why it took you that long; I guess it depends on what you're trying to do.

This is the technique I use. Hopefully I explained it the image above. I find that Physical Surface works better for me. I'm using Poser 13. Adjust the render settings for the best results. Render Settings are below.