on Just Publishing Advice:
Can a self-published book be republished?
Yes, if you have self-published a book, you can update it at any time and as often as you like.
You can change, modify, merge, or improve your book for both ebook and print versions.
You can update the cover design, change your genre and category listings and fine-tune, or find new keyword listings.
How to republish a book
The big advantage of self-publishing
It’s always possible to improve a book
Add links to an ebook
Check your formatting
Choose better categories and keywords
There is always room for improvement
Unpublish and republish