Have you ever tried to change the URL of a SharePoint document library via the library settings? Never mind, there is no option in the user interface, so let’s do it in the SharePoint Designer!
1. Go to “All Files” (don’t try to do this in the “List and Libraries” section..it won’t work!)
2. Right-click your library, rename it
3. SharePoint will update the library name and the URL
Now we’re almost done. Unfortunately, SharePoint sometimes doesn’t update the links in the quicklaunch navigation. Go to “Site Settings -> Navigation” and make sure that the new link to your library is set correct.