Tutorial
This is with regards to the legacy or old discussion forum.
Any forum moderator or site manager has the ability to edit or delete any message that is posted to the discussion forum.
When you are looking at the post, there are three choices at the bottom of the message - 'Reply, Edit and Delete.'
Clicking on 'edit' will allow you to change the message, and if you choose 'delete' you have the option to 'delete just this message' or to 'delete the entire thread'.