cant seem to delete style or rename

Im trying to clean up a keynote for a client that has some pre built styles ( whose titles happen to be in a non-english format as title) I cant seem to delete the style or rename form the menus I know how to get to (grayed out selection). Nor can I add new styles. My original thought was just to delete the non english titled style and make a new one. But I cant do either. Can this style be "locked " somewhere? and I just dont know where to look?

thank YOU