Answer:
Tell the situation to the person involved in the schedule before taking care of your personal emergency.
Explanation:
When making a schedule with other people, informing others in case we are suddenly unable to fill the schedule is considered as a social norm in almost all society.
If you decided to take care of your personal emergency without informing them, they will most likely become offended and you will damage the social relationship that you have with them.
The Spanish where the first ones to settle in North America.