DL, like NW, does not allow changes in routing for standby travel.
Really? I was scheduled to fly LAX to MSP to MKE a couple weeks ago. NW let me go standby (at kiosk checkin) on the non-stop LAX to MKE filght. I got on the flight and even got an "F" seat (gold upgrade).
It is my understanding, though, that they wouldn't let me go standby via DTW or any other hub.