Automatically name a report when exporting to PDF

Hello,

I have a form with a command button that opens my report in print
preview mode in Access 2007. When I click the Export to PDF/XPS
button, the default file name is the name of the actual report within
Access. I've used VBA to change the report caption to match a field on
my form called PROGRAM. However, this does not transfer over when I
want to save my report to pdf.

How can I make it so that when I click export to pdf/xps, the default
file name is named after a text box called PROGRAM?

Please let me know.

Thanks