my $newxlsfile = $xlsfile . '.new';
my $newxls = Spreadsheet::WriteExcelXML->new($newxlsfile); # file, NOT handle
# insert code to put updated data into $newxls
$newxls->close();
close($xlshandle);
rename($xlsfile, $xlsfile . '.bak');
rename($newxlsfile, $xlsfile);