// Create an instance of Workbook class and load the source Excel file 
Workbook workbook = new Workbook("sample.xlsx");
// Invoke Save method to save as Excel 2003 Spreadsheet XML 
workbook.Save("Spreadsheet.xml");
// Initialize an object of xmlSaveOptions class to save as plain XML data 
XmlSaveOptions xmlSaveOptions = new XmlSaveOptions();
// save the XML file by calling the Save method 
workbook.Save("data.xml", xmlSaveOptions);