When students have handed in their work they will no longer be able to modify their essay. However, a teacher can hand back work if they would like their students to continue revising their essays.
To do so, go to the class list in an activity and you have the following options.
Option 1: Hand back individual work
To hand back individual work, click the three dots icon beside the name of the student whose work you'd like to hand back.
You can then select Hand Back to return the student's work. They can now see your feedback and continue revising their essay.
Option 2: Hand back all work
To hand back all the work submitted in the activity, go to the top of the class list and click on the Hand Back All button.
Now all the students in this class who've handed in their work will see your feedback and can continue working on their essays.