The Hue and Saturation adjustment on the format menu can be a fun tool. It can also be used to adjust the tones in an off-color picture, but the Color Balance is better for fixing up photos. Changing the hue can be useful if you have a graphic you want to insert into a composition but the color isn't what you want. You can also use a series of hue shifts to make an anigif with changing colors. All the colors in an image will shift together with this tool.

You can change only one color by selecting it with the Magic Wand, converting it to an object and then shifting the hue on that object. Although it appears in the preview window that all the colors in the image are shifting, the effect will only be applied to the object.

I had selected the red flower on the left, and a little bit of the reddish pink flower up on the right had gotten included in the selection. I turned them yellow and here is the finished picture.