This month I have to rehash old business. Last year I told you how to get a searched link out for marketing to show Amazon that lots of people were searching for your book. As is the norm on the internet though, things are always evolving.
Amazon quickly got wise to this tactic and added a tiny bit of information to each search that now prevents this from being a useful tactic. There is actually a time stamp within the link now.
So! Long and short of it. Back to using the original link they provide you in your KDP account. It look like this http://www.amazon.com/gp/product/B018TDAYHS Everything past the capital letters in the link is all excess and can be deleted.
If you took my advice and went and got a shortened link from bitly or another service, you can simply go change the link there and all your marketing is still intact with the new updated link.