@JosephFait
I believe that what @NoahBoswell provided may be partially correct (I may not be thinking about this problem correctly). I will provide a possible solution on two different types of assignments - you did not specify how the test was being given (i.e. as an a regular assignment or quiz or something else).
If it is a classic quiz, it is quite simple to give the student another attempt via moderate quiz. I would use that method if all students still have access to the quiz. Just make sure you have the answers turned off for the quiz so that they can't review the answers. If the time to take the quiz has passed, just add the one student to their own time frame for the quiz. under assign to add them and then give the dates for taking the quiz. everyone else still has the same time frame.
If what you are talking about is a regular assignment where they have to submit their work, you can just change the assign to like what was mentioned above.
I do what I described above all the time where various students get an extra attempt for whatever, or need a different time frame for the assignment.
If what you see does not help or seems confusing just post back with some more information and someone should be able to help you out.
Ron
