Go to your conquer folder. (Usually C:\Program File\Conquer 2.0\) and open the ini folder, there search for StrRes.ini and change this line
PHP Code:
100079=Guild Leader
to this
PHP Code:
100079=Clan Leader
Now exit your conquer client if you have it opened and relogin, that should do it. Now ofcourse if your server is public you'd have to distribute the modified StrRes.ini to everyone who plays via a patch of some sort so they'll see the 'Clan Leader' also.