If you simply do not think you can get a good photo of your baby on that day, you may need to reschedule the appointment or find a different photographer with whom your little one has better rapport.
Whether you need to reschedule a practice or arrange separate transportation to a meet, swimming club websites are usually more efficient than phone trees these days, although a group text message can also get the word out in a jiffy.
If you are to undergo a clear liquid diet prior to a medical or surgical procedure and you don't stick to the diet, it is very important you let your physician know because they may wish to reschedule your procedure.
If you are scheduled for an interview, you'll be able to verify or reschedule your time through the system as well as verify that your documentation is still active.
Check in at the ranger station to get updates on trail and weather conditions before you head out and don't be afraid to reschedule if conditions are not ideal.
If 3 or 4 of us cannot make a dinner (or the host cannot do the date), then by all means the host can/should make an effort to reschedule.
Ask about how the photographer handles fussy babies and whether it's possible to reschedule if your baby has a rough day.
Reschedule your workouts and give yourself time to unwind.