You can delete and edit your own comments or, if you're a moderator, you can delete any comment made in your vialogue.
To delete a comment, select the trash can icon. Deleting a comment also deletes its replies.
If you are a moderator of a vialogue and wish to delete ALL comments, the quickest way to do this is to go to your vialogue’s settings page → Delete → Delete comments.
To edit a comment, select the edit icon. If you don’t see this icon, see Why can’t I edit my comment?