Here are some simple steps to do that :
1. Open the image in Editor. Select the body of the object where you want to make color replacement & right click>Layer via Copy.
2. Now go to Enhance menu>Adjust Color>Replace Color
3. In the dialog, you would see that you can use color picker under "Selection" heading to pick the color from the image you want to replace.
4. You can adjust the fuzziness slider to see what part of the object you want to be replaced with other color. in the image below, the white part in the black background(shown in above image) is the one which will be replaced with the new color. You can adjust this region using Fuzziness slider.
5. Now from the other color picker under "Replacement" heading which you want to apply as a new color in the replacement.
6. Once you are satisfied (you can preview the changes as you choose colors if preview check box is checked in the dialog), you can click "Ok".
Here are my final and initial images :