Answer

1. Connect to the published data source from Tableau Desktop.
2. Navigate to a worksheet that uses the desired data source.
3. Create a local copy of the data source by selecting Data > <data source> > Create Local Copy.
4. Save the local copy of the data source.
5. Replace the published data source with the new local data source by selecting Data > Replace data source....
6. Right-click the published data source and then select Close to close the published data source.
7. Make the desired changes to the local copy of the data source.
8. Select Data > <data source> > Publish to Server to overwrite the original published data source on Tableau Server.
9. Make sure to leave Update workbook to use the published data source selected. 

Additional Information