You can remove submissions, peer reviews, self reviews, feedback reflections and instructor reviews from the Results page.
The way to delete learner's work is the same for all of the above types of activities.
Navigate to the activity page for the work that you want to delete.
Select the option to view results at the bottom of the page.
Use the context menu on the top right of the specific learner work that you want to delete.
Select to delete the learner work.
Here is an example of the context menu shows on the Results page when you want to delete a peer review.
Learners will see their activity reset from Completed to Ready to complete, and they can complete the activity again.