Copy Work Notes From Problem To Incident

Hi,

I am writing Business Rules to Copy Work Notes from Problem to Incident. Description and Short Description work fine, but Work Notes is not working. Kindly help.

(function executeRule(current, previous /*null when async*/) {

var gr = new GlideRecord('incident');
gr.addQuery('problem_id', current.sys_id);
gr.query();
while(gr.next()){
	gr.work_notes = current.work_notes;
	gr.update();
}

})(current, previous);

Regards

Suman P.