Take a copy of an arbitrary post, page, or custom post type, change it, and make it replace the original post at a given date and time in the future. That’s what the tao-schedule-update plugin does.
Scheduling page updates is one of the missing features of WordPress that anyone running WP as a CMS is missing. Thankfully it’s easy to add.
TAO Scheduled change is a really small plugin. It only does one thing, but tries to do this the right way: Take a copy of an arbitrary post/page/cpt, change it and make it replace the original post at a given date and time in the future.