Locate the file or page you wish to rename.
In this example, we will rename an image.
Click the Move/Rename tab.
Modify the System Name field to be the new name for the file. Be sure the “Unpublish Content” box is checked, and click Submit.
Important: If you rename a file other than a folder or page, do not change the file extension (e.g., ".jpg", “.png”, “.gif”, ".doc", ".pdf")
Publish the renamed file/page.
Click the Relationships tab, and publish all relationships.
See also: Publishing FAQs