To Delete Color Keys from a Gradient Fill

From the Active Color dialog, select the Gradient Fill tab.
From the Type option menu, select the fill type.
From the Color Mode option menu, select Multiple Colors.
Click on the vertical bar, or the top button, for the required key.
The button at the top of the color key highlights.
(Optional) Use <Ctrl> data points to select additional keys to delete.
Press the <Delete> key.
Note: The first and last keys cannot be deleted. If, however, you drag another key all the way to either end of the gradient color bar, then that key will replace the end key.