If you don't pay the registration fee, it's nothing. If you have paid the fee, you may not be able to refund it! Make an appointment online, and call or SMS to remind you before seeing a doctor. Just cancel the reservation at this time.

I used to make an appointment on Quanyi.com, and they would call me the day before I went to see a doctor to remind me. If I can't go to the hospital, I can ask them to cancel my appointment. Maybe you can consult the whole medical network. The online reservation registration system is similar, and the solution should be similar!