Just happened tonight -

We had a 1:05 cumulative schedule change, departure moved up by that amount of time and just ate away at a 20+ hr layover we had.

I had agreed to the long layover mainly because it was 60K miles per person cheaper than the next best routing, but did this knowing full well that at 10 months away from travel I could probably parlay a change into getting flights I wanted.
Sure enough, a month after booking they posted a schedule change.

Called in and stated that we wanted to take a different flight out due to the departure time change, we were OK with a different connection point.
EXP agent started to say to cancel and rebook (at now MUCH higher award rates), but I gently pushed on the fact that it was a schedule change and we wanted to switch to a flight that was closer to our originally scheduled departure time.
She acquiesced after I offered the exact flights we wanted and reiterated it was the same departure date, and same destination.

All in all, a win and we get home 13 hours sooner and don't have a 20 hour layover.