Yes, made the changes, click save changes, then hit publish. No need to upload the whole book again. My experience is that the changed info shows up very fast -- a matter of a few hours, sometimes just minutes.
I just changed the price on one of my books, and while I was at it, I changed the publisher as well. (I had been using the name of the paper publisher, but of course that wasn't right.) The changes showed up within a couple days.