Step 1 : Click on the Control Panel link in your course.
Step 2 : Click on the Grade Center link.
Step 3 : Find the Exam or Survey that needs to be reset, and mouse over the cell containing the "In Progress" icon so that the double arrow is visible as shown:
Step 4: Click on the double down arrow, and select "Grade Details" from the options available.
Step 5: On the Grade Details page, look at the "Attempts" area. Here you will see a "Clear Attempt" button.
Step 6: Click the "Clear Attempt" button.
Step 7 : Click OK on the pop-up, asking if you are sure you would like to clear the attempt.
Step 8 : Now the "In Progress" icon should be replaced with a hyphen. This shows that the attempt has been cleared.