$(document).ready(function () {
   //render and initialize kendoSpreadsheet:
   $("#spreadsheet").kendoSpreadsheet({
        columns: 20,
        rows: 200,
        toolbar: true,
        sheetsbar: true,
        sheets: mySheets,
        width: "100%"
   });
    
   //render and initialize kendoButton:
   $("#load-new-sheet-btn").kendoButton({
                icon: "forward",
                themeColor: "primary",
                click: swapSheets // want to render new set of sheets. Is this possible?
    });
 });

 //assign a different JavaScript object to the sheets: option parameter (this doesn't seem to refresh the spreadsheet component/control:
 function swapSheets() 
 {
     var currSpreadSheet = $("#spreadsheet").data("kendoSpreadsheet");

     console.log("BEFORE clearing sheets: currentSpreadSheet contents: ",  currSpreadSheet.options.sheets)
     currSpreadSheet.options.sheets = mySheetsTwo;

     console.log("AFTER clearing  sheets: currentSpreadSheet contents: ", currSpreadSheet.options.sheets);
     currSpreadSheet.refresh();
 }

  @(Html.Kendo().Spreadsheet()
            .Name("spreadsheet").HtmlAttributes(new { style = "width:100%;" })

        )
<script>
$(document).ready( function () {
        var spreadsheet = $("#spreadsheet").data("kendoSpreadsheet");
        
 $.ajax({
    type: "POST",
    url: '@Url.Action("GetFileFromDetails", "Spreadsheets")',
            contentType: "application/json; charset=utf-8",
            data: { data: myData },
            dataType: "json",
            success: function (recData) {
                //alert(recData);
                spreadsheet.fromJSON(recData.response);
            },
            error: function (ex) {
                alert(ex);
            }
        });
  });
        </script>

  [HttpPost]
        public ActionResult GetFileFromDetails()
        {
           

var workbook = Workbook.Load(file.InputStream, Path.GetExtension(file.FileName));
            return Content(workbook.ToJson(), Telerik.Web.Spreadsheet.MimeTypes.JSON);

        }

  [HttpPost]
        public ActionResult Upload(HttpPostedFileBase file)
        {            
            var workbook = Workbook.Load(file.InputStream, Path.GetExtension(file.FileName));
            return Content(workbook.ToJson(), Telerik.Web.Spreadsheet.MimeTypes.JSON);
        }