Hold on a moment!!
That would work, but you can also manipulate the FRX as a table and do it that way.
For example, if you search on support.microsoft.com under VFP for "duplex" you'll see some articles mentioned.
Basically, you can select things like paper size, bin/source, duplex, etc by altering the value of the EXPR column for OBJTYPE=53 etc.
This is a lot easier, but remember that (usually), you'll want to manipulate a copy of your FRX. Issuing something like
use masterreport.frx
copy to (newreport.frx)
will also copy the associated .frt file
I hope this helps.
The other place to look is on
www.news2news.com - lots of useful stuff on accessing devmode structures that you might need.
Regards
Simon