Solution:

1) Select the 'Format' menu and select 'Slide Color Scheme...'. (The Color Scheme dialog box appears.)
2) Click the 'Custom' tab.
NOTE: Each color in the 'Scheme Colors' group is indicated with a line and a tag, for example, Background, Shadows, Fills, Title Text, etc.
Scheme Colors
3) Select the desired scheme color to change from the 'Scheme Colors' group. (The selected scheme color is highlighted.)
4) Click 'Change Color...'. (The appropriate dialog box appears.)
5) Do one of the following:

a) To select a standard color:

1] Click the 'Standard' tab.
2] Select the desired color. (The selected color is highlighted and displayed in the New Color box in the lower right hand corner.)
Standard Color
3] (Optional) Click 'Preview' to preview color selections without making any permanent changes.
NOTE: After the color changes have been previewed, 'Preview' becomes dimmed until another color is selected.
4] Click 'OK'. (The Color Scheme dialog box reappears.)

b) To customize a color:

1] Click the 'Custom' tab.
Custom Color
2] Press and hold down the mouse button over the arrow.
3] Drag the arrow up or down the vertical color bar to change the luminance.
NOTE: The numbers located in the 'Lum', 'Red', 'Green' and 'Blue' list boxes change as this is done. The numbers can also be typed in the related boxes.
4] Press and hold down the left mouse button over the cross-hair.
5] Drag the cross-hair over the desired color.
NOTE: The numbers in the 'Hue', 'Sat', 'Red', 'Green' and 'Blue' boxes change as this is done. The numbers can also be typed in the related boxes.
6] (Optional) Click 'Preview' to preview color selections without making any permanent changes.
NOTE: After the customized color changes have been previewed, 'Preview' becomes dimmed until another customized color is adjusted.
7] Click 'OK'. (The Color Scheme dialog box reappears.)

6) To add the new color scheme to the 'Standard Color Schemes' group, click 'Add as Standard Scheme'.
'Add as Standard Scheme' button
NOTE: After 'Add as Standard Scheme' has been selected, 'Add as Standard Scheme' becomes dimmed until another color scheme is created.
7) (Optional) Click 'Preview' to preview the new color scheme without making any permanent changes.
NOTE: After the color scheme changes have been previewed, 'Preview' becomes dimmed until another color scheme is adjusted.
8) Do one of the following:

a) Click 'Apply to All' to apply the new color scheme to ALL the slides in the presentation.
b) Click 'Apply' to apply the new color scheme to the current slide.
c) Click 'Cancel' to abort the new color scheme. NOTE: If 'Apply to All' or 'Apply' is selected before 'Add as Standard Scheme', the new color scheme will not be added to the 'Standard Color Schemes' group. However, the new color choices will remain in the 'Schemes Color' group the next time 'Color Scheme' dialog box is opened.