Clear jQuery Chosen select options on change event - jquery-chosen

Question

I'm having some difficulty clearing previous jQuery Chosen select options on a change function from another select.
I tried
$(".chosen-workOrderFormModal_machineSelection").val('').trigger("chosen:updated"); but that did not work.
I am using Chosen v1.8.5
$('.chosen-workOrderFormModal_systemSelection').on('change', function(evt, params) {
systemCode=$('#workOrderFormModal_systemSelection').chosen().val();
$('#workOrderFormModal_systemSelection_chosen').css('color', '#495057');
$('#workOrderFormModal_systemSelection_chosen').css('border', 'none');
machineCodeSelect = '';
//*Start -getMachineSelectionData.php AJAX
$.ajax
({
type: "POST",
url: "getMachineSelectionData.php",
data: { locationCode: userLocationCode,
systemCode: systemCode,},
dataType: 'json',
cache: false,
success: function(data) {
$.each(data, function(i, machine){
machineCodeSelect += '<option value="' + machine.machineCode + '">' + machine.machineDescription + '</option>';
});
$('#workOrderFormModal_machineSelection').append('Select Machine...');
$('#workOrderFormModal_machineSelection').append(machineCodeSelect);
$(".chosen-workOrderFormModal_machineSelection").val('').trigger("chosen:updated");
$('.chosen-workOrderFormModal_machineSelection').chosen({
disable_search_threshold: 10,
no_results_text: 'Machine Not Found',
width:'271px',
});
}
}); //* END -getMachineSelectionData.php AJAX
$('#workOrderFormModal_machineSelection').attr('readonly', false);
$('#workOrderFormModal_machineSelection').removeAttr('disabled');
$(".chosen-workOrderFormModal_machineSelection").val('').trigger("chosen:updated");
$("#workOrderFormModal_machineSelection_chosen > a > span" ).text('Select Machine...')
});