If you’re planning major changes to your book that will warrant a brand new paperback edition, or if you’ve acquired your own ISBN number and want to use that instead of the free issue CreateSpace ISBN, it’s not a complicated process. Unless you unpublish your Kindle book and start from scratch with that too, you won’t even lose your reviews.
So, assuming you will simply upload your updated eBook file to the currently published Kindle book keeping its Amazon assigned ASIN number, what you need to do is prepare your paperback with its new ISBN number in the front matter, the edition number, and also the new Published By information – don’t use your own name unless you really, really, really want to. Think about this before you buy your ISBN’s and call your publishing business something different. As a self-publishing author you are a publisher, and there’s no reason not to give your business a nice professional name.
When you look at the various editions of the same book from traditionally published authors they generally have a totally revamped look for each of them, so you might want to update your cover – even if only with a tweak or two, that will make it distinguishable from the first edition. Publish this from scratch with CreateSpace as a totally new project.
Contact CreateSpace and let them know that you wish to retire the first edition. This will result in an out of print notice on its Amazon page, which means that new print versions of it can’t be ordered, but that page won’t be taken down due to Amazon’s policy on the sale of used books. CreateSpace will however unlink this from the Kindle book product detail page, and the link the new edition to that instead, and all reviews already received for the eBook will remain right there. Easy as pie.
There’s no harm in revamping some of your backlist this way once you have more readers than you did when you published them. Add details, chapters, images, maps, tweak, modernise your covers and start an old book on a wonderful fresh journey. Obviously if your updates don’t include new ISBN numbers you can update without starting a new project, but sometimes especially if your first paperback didn’t do very well then beginning again could very well be the way to go.