How to change the name of a PDF invoice emailed from QuickBooks?

I usually email my clients an invoice from QB - but each PDF it creates has the exact same name. If I am sending out more than one invoice to the same client on the same day or later, I run the risk of them accidentally overwriting the previous PDF when saving it to their PC . Is there a way to change the name WITHIN QB on an invoice by invoice basis (not after it's created)?