That issue has NOW been solved.
All you need to do is:
1) Publish the new edition [UPDATE: Please note that Kobo has informed me that, to reduce customer confusion, they don't allow duplicate listings on the site, so, once you have the ISBN for the new version, it's best to REMOVE the original/old listing]
2) Collect the Title, Author, ISBN for the old edition as well as for the new edition
3) Email your request to have the ratings and reviews moved to [email protected]
4) Wait until confirmation the ratings and reviews are completed and then delist/remove the old version via the original source you used to publish it.
It's THAT simple. Of course, if you prefer visuals and more details, check out the attached PDF.