I was traveling recently and wanted to stay an extra day. I called Delta who told me that with the change fee and the additional ticket price, it would be over $650.00 extra. I declined, telling them that I would just return home as originally planned. Two days later I got up in way before the sun came up to make my way to the airport some distance away. As we are approaching the time to board, there is an announcement from the service desk saying they over sold the flight by 4 seats and were prepared to offer someone $400.00 to stay an extra day.