This article provides manual and programmatic methods of clearing the SharePoint designer cache for both SharePoint 2010 and 2013. Clearing the cache will remove any past connection history as well provide you a “clean slate” to work from.
SharePoint Designer
How To Change A SharePoint List Or Library URL
All versions of the SharePoint user interface provide an option to change the title (or display name) of a list or library. Changing SharePoint library URL (or internal name), however, is not exactly very intuitive. We will discuss the process in this article.