Within your classrooms, you can easily edit assignment Open, Due and Close dates, and Remove (or Delete) an assignment.
From you Classes list, select the classroom you wish to edit assignments within:
Next, click to "View Class Assignments":
In your list of Assignments, you will see a gray pencil icon to the right of each Assignment listed.
From here, you can click to edit dates.
To remove 1 or more assignments at a time, simply click on the check box to the left of the assignment(s) and then click on the red "Remove Assignments" button.
Learn how to remove an assignment for individual students.