Change field on a specified date - fire change actions: Case Management

I am creating an
application for case management.   A case can have a status of being open, closed or pending.   When a case is put into 'pending' status, a date is set for the status to change to 'open'. 

How do I get the action to fire without opening or editing the record?

The idea is so that users have a work queue (dashboard report) which only shows cases in open status, not pending or closed. 

Any advice appreciated