As others have said, versioning is the way to "republish" work on the new site. I use it quite a bit. You can have many versions of the same chapter, usually as a way to hang onto old reviews associated with prior versions of the same chapter. For the most part, the workflow is similar to adding a new chapter, beginning with the Add Chapter step. When you reach the page where you specify the chapter number and chapter notes, choose the same chapter number as the one you want to replace, but increase the version number. As you follow the wizard, you'll have a chance to publish the new version, make it active, and make the older version inactive. If you want, you can keep older versions active as well, assuming you want feedback comparing the versions.