Good night, what should I do to change the date of the ticket, due to a medical emergency?

If they change it, but you will have to pay another ticket, if you find it available on the date you are looking for, it is a lost case, it has already happened to me. Good luck.

Typically you cannot change the date. Unless you bought the insurance for the ticket. However if you contact AeroMexico directly, you may be able to persuade them to change the date. Good luck