If your title has never been in distribution, any changes can be made to your title's metadata and content.
If your title has been in distribution, industry-standard says only 20% of your book's content or less can be updated. Any substantial changes are not allowed, as they typically result in distribution issues. For example, changing from a paperback to a hardcover is not allowed.
*If you are updating more than 20% of your book, we recommend using a new ISBN and setting up a new title on your account (i.e. Revised Edition).
If your title has been in distribution and you only need to make minor changes to the metadata, you may do so. Examples include updating a subject code, book description, or review quotes.