Revisionize is a free WordPress plugin that clones your post, page or CPT to a draft, which gives you the freedom to tweak and edit without modifying the live, published content. When the revision is published, your content changes will be copied back to the original post. Alternatively, schedule the revision to publish your content sometime in the future.
These paid addons provide extra functionality to make Revisionize even more powerful. Purchase once and get a lifetime of updates and improvements.