Event not being called

Hi,
I am calling an event from another event, but its not being called, any idea what I am missing?

frappe.ui.form.on("Sales Order Custom Parts", "alternate_option", function(frm, cdt, cdn) {
var d= locals[cdt][cdn];
frappe.model.set_value(cdt, cdn, "item_code", d.alternate_option);
cur_frm.add_fetch("item", "item_name", "item_name");
cur_frm.add_fetch("item", "description", "description");
frappe.model.set_value(cdt, cdn, "alternate_option", "");
refresh_field("sales_order_custom_parts");
frm.trigger("sales_order_custom_parts", 'more_options');
});

frappe.ui.form.on("Sales Order Custom Parts", "more_options", function(frm, cdt, cdn) {
msgprint("More Options Called");
var d= locals[cdt][cdn];

var d1 =  {   
              "item_code": d.item_code 
         };   
frappe.call({
    		method: "library_management.update_items.alternate_item",
             	args: d1,
    		callback: function(r)
				{ 
				a = JSON.parse(JSON.stringify(r.message));
				}
    	});
});