Begin by clicking on the "Blog" tab in the Sidebar, then click the "Scheduled" link. This will bring you to the eMerge content calendar. You can also click the "View Calendar" button at the top of your eMerge account.
Blogs will be indicated by their channel icon (Tumblr, Wordpress, Blogger, etc.) along with the blog's title and the time it is scheduled to be posted.
Click the down-arrow next to the post you wish to edit to see the title of the blog post, and also see the options to Edit, Copy and Delete the post (Posts that have already been sent out will only have the option to copy).
Edit the post as needed or change the date/time to whatever you wish.