You can delete only for a short period after you post. You can edit a post for a bit longer - then it becomes fixed.
If there is a really good reason it has to be deleted - or you think something should be changed - hit the notify button and a moderator may do what you suggest/request.
In a time of universal deceit - telling the truth is a revolutionary act. George Orwell
When the debate is lost, slander becomes the tool of the loser. Socrates