Songtrix

You can open the style file and then choose Save As to create an additional copy with a new name.

Or you can just use Windows Explorer to rename the style file in the usual way.  If you used the default installation folder, you will find the style files in:

C:\Program Files\ChordWizard Songtrix Beta 3.0\Styles

Once the file is renamed you will need to restart Songtrix so it scans the available files again.  Any song which depend on the old filename will need to be updated next time they are opened.