I cannot edit any feature in my clan culture. Whether I am changing the name or changing the motto, I am always told, "The clan name is already in use." This even shows up when I keep my clan name constant, and when I do try to change the clan name, I search for that clan name to see if that name is in use. Even if that clan name is available, Bungie tells me that it isn't available. And yes, I am the clan founder.