Visit the official United Airlines website.
Navigate to the "My Trips" tab.
Enter your Confirmation Number and Last Name.
Click "Search" to find your booking.
Select the flight you wish to cancel.
Click "Cancel Trip."
In the description box, explain that you are canceling due to illness.
Follow the on-screen prompts to complete the process.
You will receive a confirmation email regarding the cancellation.
United Airlines will review your request and issue a refund based on fare conditions and your reason for canceling.
For more information aboutUnited Airlines Passengers Sickpolicies and assistance, please visit their official website or contact customer service.