Call the people who summoned you for the answer to your question, because they get calls all day long from people who want out. I have bad hearing and called them about that, and they agreed that I don't have to go for my summons which happens to be next month.
You will need a doctor's note. When you get your "packet" from the Court it will explain what you can do (reschedule, change location, etc) and what is needed to be excused (doctor's note). Good luck!