To change the color of only one element in your presentation on only one slide:
Don't need to use the Color Scheme dialog box.
Instead, select the object,
open the Color dialog box for the color you want to change:
the fill - border - line - text, and so on.
The fill is the inside pattern or color of an object/background.
The fill is the color inside the border.
PowerPoint fill effects include
gradients, textures, patterns, and pictures.
The Color dialog box looks the same from one element to another.
When you work with color but printing handouts in black and white:
preview color presentations in grayscale and black and white.