If after sharing an assignment, you notice an issue with the due date or points you can easily make an edit. You can do this by going to your Timeline then clicking on the assignment. This will take you to the grading window. From there, click the edit button on the top left pictured here:
Once you click the button, you will get the option to edit the assignment it. Please note, you can only edit the following values:
Who it's assigned to - You can only remove students from assignments if you have not graded them for that assignment yet.
Points including making the assignment Formative or Summative.
At this time, we don't have the functionality to edit the contents of an assignment after it's been shared. If you need to modify a question or remove a question from the assignment, you'll have to edit and re-share the assignment with students.
Editing on Mobile
On mobile, simply tap "Class" then tap on the desired assignment. On the top right, there is an option to edit the assignment.