Cannot publish new version of Rise 360

Hi, my colleague created a Rise 360 e-learning and I've taken over editing for it. I was set as Manager and she as Owner. I could edit and publish for Review 360. However, when I wanted to re-publish I wasn't able to publish as a new version of an existing item, only to publish as a new item - this would have given my SMEs a different link and possibly lose all their comments right? We decided to swap our access in settings. I'm now the owner and she is editor. I'm still getting the same issue though, I can't publish an existing version. Your advice is greatly appreciated, thanks :)