Select the Modify button next to the Display Option labeled Letter
Since WWU doesn't use the A+ grade, you may want to remove this line if your course includes it. Select the Remove button next to the A+ line
To adjust the number values, simply type new values into the min and max values of the letters you want to change. Note that the minimum value of the higher grade must be exactly equal to the maximum value of the grade level directly below it as shown in the picture below.
Press Submit when you are finished modifying the values of the letter grades.