Assignment - How to revert a file submission to a draft
This will allow the students to add additional documents to their submission. (Only if you allow more than one file submission)
Clicking on the assignment itself from the Moodle Course Main page.
Click on the View/grade all submissions
Locate the student, placing a check in the box, then go to the bottom of the page using the With selected... drop down select Revert the submission to draft status. Finally click on Go