You can rename all documents associated with a Document Type that uses an Auto-Name string by changing the string.
If you make a change to static text or variables contained in the Auto-Name field, select the Rename All Documents of This Document Type check box to re-name all documents associated with the Document Type or Folder Type in the system.
Depending on your system's configuration, updating a Document Type's Auto-Name string may take a long time to complete, and it may significantly impact system performance. If your database contains more than 100,000 documents in a Document Type you plan to update, it is strongly recommended that you either test the update in a backup version of the Production database or contact your first line of support to discuss alternative options.