You can update the file and settings of a book without changing the resource ID. This is useful for situations where business needs have changed, or errata in a book needs to be corrected.
How does this work?
On the "Book" page in your account select the book that needs to be updated.
Click "Edit" next to the book title you selected.
Make the needed changes, this includes changing the book file, or the DRM settings.
Click "Update Details"
Note: The changes will reflect on future downloads/fulfillment. End users who have previously fulfilled the book will still see the old version of the book.