<script runat="server">
    Platform.Load("core","1.1.5");
    var prox = new Script.Util.WSProxy();
    var de = {
        CustomerKey: 'AA554FF4-B0FF-4F1E-ADA9-123123123',
        Name: 'NewName'
    };
    var resp = prox.updateItem("DataExtension", de);
    Write("<br>Response: " + resp.Results[0].StatusMessage);
</script>