Conversion from Excel to PDF


I want to use Libreoffice to convert from XLSX format to PDF via command line.
I know the command
soffice -headless -convert-to pdf -outdir “D:\PDF” “D:\XLSX\FILE.XLSX”

But is it also possible only to convert XLSX files from which a PDF file is not created yet? I don’t want LibreOffice to overwrite existing files.
Thank you