using below script i need to update ritm closer comments

i am using below script to update closer comments in ritm but it's inserting the dummy record not updating record

 var grval = new GlideRecord('sc_req_item');
            grval.addQuery('sys_id','e03fae4b477eb6189c5e5cbd436d439e');
			grval.query();
            grval.close_notes = 'test';
            grval.update();

Any idea on this please let me know