Well,
(1) First, you make sure that your Preference is for "single message", not "guestbook."
(2) you click your post, and right below your message you see a button that says "delete this message" and a blank box for your Password. Type in the password and click the button. ... ... .....If you don't know your password, I don't know what to do other than call for Greg.

Robt.