If the ASIN/ISBN remains the same you can add them as alternate cover editions. They will show as different editions of the same book, they cannot be merged. If you want the new cover to display on author page and searches you can select that edition as primary/default edition.
I have some book covers that have changed. I understand that they can't be switched out and may need to be added as new editions. Here are the books:
https://www.goodreads.com/book/show/1...
new cover on amazon link: https://a.co/d/f2srfHv
This one had a placeholder cover: https://www.goodreads.com/book/show/2...
new cover on amazon link: https://a.co/d/4TOJ2od
https://www.goodreads.com/book/show/6...
new cover: https://a.co/d/2LcZZu1
https://www.goodreads.com/book/show/6...
new cover: https://a.co/d/12nmy5d
https://www.goodreads.com/book/show/7...
new cover: https://a.co/d/ey2CZfT
https://www.goodreads.com/book/show/1...
new cover: https://a.co/d/gIScvJG
Once the new covers are uploaded, am I able to merge them, or will they always show as separate books?
Thank you SO MUCH!