How to prevent overwriting file on server (e.g. save as file_1.pdf)

Hi,

I've created a rule that saves my PDF to my server. My issue is that if I edit and recreate the PDF again, it will use the same filename and overwrite the first PDF that was created.

Is there anyway to add something to my rule to prevent overwriting my PDFs? Ideally, I'd like to have each modification saved as its own PDF (to act as an audit trail of sorts).

Thanks