If you want to avoid the cancellation fee, then as per southwest vacations flight cancellation policy, you must cancel the booking within 24 hours of purchase. You can check out the complete refund process below to ensure you are doing it correctly. For more info call here +1(802)-216-4422 or visit here - https://www.faresglob.com/article/how-long-does-it-take-to-get-a-refund-from-southwest-vacations