C＃将Excel 2007（xlsx）文件转换为Excel 2003（xls）文件

I am working on a console application which will convert xlsx file into xls file. I don't want to rename it from xlsx to xls because it will get opened in excel 2007 but it will be shown as corrupted file in excel 2003. Looking for a way which will load the document and then it will be saved as xls format.I am working on a console application which wil