You can edit posts that you have written to your blog at any time. To edit, click the icon at the top right of the post on either the blog home page or in the post page itself. The icon can be found under the recommend star. An edit option will appear in the drop down menu.
You can only edit replies written in response to another author's post within the first 15 minutes of publication. After 15 minutes the reply becomes part of the public conversation and cannot be altered. It is currently not possible to completely delete a reply, even within the 15 minute window.
To edit a reply, hover over your reply to reveal an icon at the top right of the post, above the recommend and reply icons. Click the icon to reveal a drop down menu with an edit button. Click the edit button to adjust your reply.