Switching from CreateSpace to KDP Print
David Gaughran, upon hearing the rumors that CreateSpace will be closing, did some testing to see what possible issues users might encounter.
He spells out all the steps necessary for switching to KDP Print (and recommends doing that sooner rather than later) in this blog post.
If you’re not convinced you want to transition to KDP Print, Gaughran has some commentary on alternatives at the end of the post as well.