* open the file
* Choose the "Replace Color" command. (In my version this is found by clicking: Enhance, Adjust Color, Replace Color)
* Click on the color you want to change
* Adjust the 3 slider bars until you get the color and look you desire
* Click "OK" and you're done!
* You may need to do this multiple times for a file, depending on how many colors you are wishing to change.
Here are three of my earlier files with the above technique applied: