<div id="spreadsheet"></div>
<script type="text/javascript" charset="utf-8">

    $("#spreadsheet").kendoSpreadsheet();

    var spreadsheet = $("#spreadsheet").data("kendoSpreadsheet");

    var sheet = spreadsheet.activeSheet();

    sheet.range("A1:B2").merge();
    sheet.range("B3:C3").merge();
    sheet.range("A1:D4").unmerge(); // this will unmerge both merged cells.
</script>