how to edit a blog page that can not be accessed from the dashboard
What exactly do you mean by this? You cannot log in? Or you are not site’s admin therefore cannot edit Posts/Pages created by another author or admin?
Or, do you mean that your single.php template file does not have the “Edit This Page” link which appears when you’re logged in and thereby makes it easy for you to edit the Page/Post right away without having to go to dashboard?
You’ve been a member for six hours. This is your only post. I don’t see how anyone could help you considering you haven’t asked one single question yet anywhere in these forums.
<rant> For someone whose occupation is “education”, you have a lot to learn. </rant>