If you make a copy of a publishing style in the same subfolder as the original, the style name will be listed twice on the Formats and Options page in the Publishing Wizard. In order to rename the publishing style, you must modify a line in the style.resources.xml file for the appropriate language in the Lang folder for the publishing style.
In the package, open the lang folder and then the folder for the appropriate language. Open the style.resources.xml in any text editor, such as Notepad. Near the top of the file there should be a line that has the name of the style in between <Resource ID> and </Resource> codes. For example, for the System Process style, the line looks like this:
<Resource Id="StyleName">System Process</Resource>
To change the name of the style, edit the text between the codes. Save and close the file and save the style package.