To change Swiss Airlines flight booking online, log in to your Swiss Airlines account on the official website. Navigate to the "Manage Booking" section, where you can select the flight you wish to change. Follow the prompts to modify your booking details, such as dates, times, or destinations. Confirm any changes and proceed with payment if applicable. Ensure to review the updated itinerary before finalizing. For further assistance, contact Swiss Airlines customer support at 1-877-507-7341 for personalized guidance.