If you would like to change the availability or due date for an individual student, or students, please follow How do I assign an assignment to an individual student? from Canvas community. 

When giving students an extension on a quiz or assignment, it’s possible for an instructor to unassign from the rest of the class. However, you can typically recover these students’ submissions by reassigning the grade item to everyone else. Please see the next section, How do I reassign an assignment to Everyone Else? for more details.

When creating or editing an assignment, you can assign an assignment to individual students, and set different due and availability dates for individual students while it is assigned to the rest of the class. Only the student(s) specified in the assignment details can view the assignment. 

1. Open Assignments
   
   

2. Locate the assignment you need to edit, and open it.

3. Select the edit button
   

4. When you assignment details page opens, scroll down to the field Assign. 

5. If you already have assigned this and need to add another due date, select +Add
   
   

6. If you previously assigned this to everyone in the class and need to recover grades, type Everyone into the Assign To field. This will let you assign it to Everyone Else.
   
   

7. Select Due, Available From, and Until, Dates for each group to which this is assigned.
   

8. Select the Save Button.

9. Navigate to Gradebook

10. Find the assignment in Gradebook. The grades should be available once again.