You can undo a student test submission to allow a student to return to a test. 
Prerequisites
To undo a student test submission, students must have Complete or Marked Complete test statuses
Step-by-Step
- From TestIng, select Students in Sessions.  
 
- Click Add a Session.  
 
- Type a session name into the search field, and click the checkbox next to the session.
  
 
- Click Add Selected.  
 
- Type a student name into the search field, and click the checkbox next to the student test.  
 
- Click Select Tasks, select Undo Student TestsSubmissions, and click Start.  
 
- Select the checkbox next to the student test or unit of a test to confirm your selection.
  
 
- Click Undo Submissions.  
 
 
 
 
What's Next? (Optional)
After you undo a student test submission, the student test status is Exited. You, then, must Resume the student test, to allow the student to test.