If you are talking about this one, then no, you can't edit it since it is hidden (it lacks abilities, items, etc.)
But if you ever want to edit a post that isn't hidden, it's simple. Go to the bottom of your post and look to the right. There will be three buttons available: edit, comment and hide. Click the edit button, and from there it's straightforward.
If you have any questions regarding this, leave a comment.