If you wish to remove the grade adjustment that was applied to an assessment...
1. From your course dashboard click 'View Results'.
2. Go to the 'Responses' tab and click the 'Adjust Grades' button.
3. Set the grade adjustment to Zero (0).
4. Click 'Save'.
6. The 'Total' column will be removed from the 'Responses' tab and the students' grades will be reverted to their original marks.