code: public static base_response change(nitro_service client, appfwsignatures resource) throws Exception {
  		appfwsignatures updateresource = new appfwsignatures();
  		updateresource.name = resource.name;
  		updateresource.mergedefault = resource.mergedefault;
  		return updateresource.perform_operation(client,"update");
  	}
docs: Use this API to change appfwsignatures.