How do I reset a student's assignment?

Learn how to let a student resume work on a test that has been submitted, or start anew.

This article describes how to reset an assignment for one student at a time.

If you need to unlock an assignment for your whole class, see this article:

You can reset a student's assignment at any point. You'll choose whether to have them continue from where they left off, or start from scratch.

If the student's due date has passed, start by updating it. You can learn how below:
How do I adjust due dates for individual students? | Derivita Support Center
Open the assignment
In the top right, click Students to see the list of students
Find the student and click the 3 dots to the right of their name
Choose Reset Student:

Resetting a student's assignment won't affect their grade in the LMS gradebook. But once they submit it again, it'll update with their new grade.