Once you have created a forum posting, you have 15 minutes to either delete or make changes to it. After the time has expired, you would have to contact your instructor and request to have the posting removed for you.

Your post would look similar to the image below, where your post will include several text links located lower right of the post. 

1. Click the Delete text link 

A Confirmation prompt appear to ensure you want to delete the current post.
2. Click Continue 

The posting is removed from the forum.