Suppose you have a post publish recenlty or some times ago. It may be days, months, years etc. Now you want to republish that post want to make some changes or change some taxonomies. Also you want to republish that post on a particular date in future automatically. You can do it by using this feature. Just click on Scheduled Republish link from post row or post edit screen and it will copy your original post. Now you can make any changes to that copied post and scheduled it for a future date. Plugin will delete the original post when this new post is being published on the previously specified future date. It will delete your original post when the modified post will be published.