Over the years, canceling a pre-booked ticket with Southwest Airlines has gotten fairly simple. You may do it yourself by visiting Southwest's official website, or you can contact Southwest customer service staff to speak with a real representative of Southwest Airlines by dialing one of their phone numbers. They will also explain their cancellation policy to you. The policy outlines all of Southwest Airlines' terms and circumstances for every flight cancellation. The staff makes certain that you do not incur any excessive losses as a result of your cancellations and that you receive a complete refund.
See also: Frontier Airlines Cancellation Policy