On the Playground app, click on the Roster icon at the top. Find the student who's absence needs to be edited and click on their name. Click on the Feed tab on their student profile.
Find the absence post in their specific feed. Click the three dots in the top right corner of the absence post and click "Edit post". Make any necessary changes, such as editing the end time, reason, or description. Once all edits have been made, click "Save" in the top right corner.