DL2189 is 1:35PM flight. DL2209 is the 4:15PM flight and is still bookable. Were you originally booked on that flight? Presumably, you are connecting to DL1759 at 8:25PM (which is also still bookable). As noted above, a schedule change is unlikely at this point and both of these flights are operating with the exact same times and exact same equipment (739's) as today's flights. Further, they've been operating with same flight nums and equipment and roughly same departure times for several months now.

https://flightaware.com/live/flight/DAL2189/history/160
https://flightaware.com/live/flight/DAL2209/history/160