User Overrides provide the ability to override specific settings for a student on an assignment. Only settings specified in the override will be changed, and all other settings will remain the same.
Example: If you override the open date for a set of students, then the students will see the new date instead of the original one that you set, but all other settings will remain the same. This includes the close date originally set for the assignment.
From the course page, use the following steps to add a User Override.
Select the module the assignment is in. Example: Chapter 1
Select Edit to the right of the assignment.
Select Set user overrides.
Select Add user override.