Yes. When I checked in for my flight at BWI, the monitor indicated that the flight would be delayed for about 30 minutes. While on my way from the counter to the security lines, I glanced at another monitor and saw that the delay was now 4 hours, so I couldn't make my connection at JFK. After consultation with a supervisor, the agent at the desk offered to put me on BA's BWI-LHR-STR flight later that evening. Since that would have involved waiting at BWI for 5-6 hours and arriving at STR in the late afternoon, I asked if I could wait a day and change the flight to DCA-JFK-DUS-STR. AA agreed immediately.