I broke my femur back in April and had a few domestic trips and an international booked and was PM at the time and called the PM desk and they just gave me credits to use within a year of the date that I booked the various trips. They asked for my surgeons name and phone but AFAIK they never called him. No change fees.
For the international ticket I was required to use the funds on another international ticket and it had to be booked in the same class of service.