Selling orphan seats

I realize orphan seats are not desirable, but they can still occur.

I don't want to cannibalize sales, but selling orphan seats may be an option for our Marketing director.

I searched existing reports, the forums, and TASK (Shared Reports), but couldn't find much help.

Has anyone tried to sell orphan seats (maybe an hour before a performance)? 
Is there an existing report that can be used to display these orphan seats?
If an existing report doesn't exist, has anyone developed an SSRS report that displays orphan seats for a specific performance?

Thanks
Wendell Baskin
Bass Hall - Fort Worth