While logged in, click "My Blog Posts" from the "User Menu" on in the upper left corner of the page to see all of your blog posts. You will notice links to "Edit" or "Delete" under each blog entry. If you wish to edit your blog post, click "Edit", make your changes and click the "Save" button. If you want to delete it, click "Delete", the post will be permanently removed from the site.
I'm a good hearted human