Go to the editor, open course settings and change the course completion to "manual". If the student completes all work in the course(that is visible to them), then the default is to mark the course complete for the student. I've had many teachers do this in the past. You'll need to reset the enrollment to active in the admin profile to get them back in the course with their scores intact after changing the course setting.
Thank you so much for your response! I do want to extend my question with are there any specifics on where my administrator should go to reset the enrollment to active? We are all new to this and she has mentioned that she cannot find where to do this.
Sure thing. Admin>courses>locate course>enrollments tab. Here you can check the boxes of the student enrollments you would like to update. Change them from complete to active.