/// <summary>
        /// PutReference()
        /// Static method which is responsible
        /// for manually updating the patient list in Canvas Oncology App
        /// </summary>
        public static void doReferenceUpdate()
        {
            API settings = new API();

            // make new canvas object
            Canvas c = new Canvas();

            // set the rows for the object based on the data set
            CanvasUtility.SetCanvasRows(c);

            // set canvas url
            CanvasUtility.SetCanvasURL(c,
                                       Canvas.RequestType.ReferencePut);

            // don't process request if there are no rows avaliable
            if (c.Rows.Count == 0)
            {
                return;
            }

            // get the last identity
            Identity lastIdentity = IdentityController.GetLastIdentity();

            // update the text file
            FileStoreUtility.UpdateIndex(lastIdentity.lastId.ToString());

            // make xml
            XMLController.BuildXML(c);

            // get payload
            string XMLPayload = File.ReadAllText(settings.XML_FILE_NAME);

            // make request to update fields
            XMLController.doRequest(c, XMLPayload);
        }