As the author of a comment, you can edit or delete it. Filter the moments you would like to see and comments related to them (use Moment type + More filters to do this).

In the list of moments, find the one with a comment you would like to edit or delete and click on it.

When you click on it, the window with moment and comment details will open. Find 3 dots right next to your comment and edit and delete button will be there.

When you're done editing, click save or cancel. Note that your edit will generate a notification to the other users in the session once you click save.

Before you delete a comment, you will need to select "yes". Note that deleted comments cannot be retrieved.