Convert PLS to WMA

You can't convert Multimedia Playlist Files to Windows Media Audio Files (.pls to .wma conversion), since PLS playlists do not contain any media data, they only reference existing media files on your device.

If for some reason you want to convert such media files referenced by your PLS playlist to other formats, you will first  have to locate/download those files. You can then easily convert those files using most available media editing programs or (online) conversion tools.

Simply put, it is impossible to convert PLS to WMA directly.
Thus, there is no so-called pls to wma converter or a free online pls to wma converter to be found.