I had scheduled a trip to Puerto Rico through United Airlines. Unfortunately a work trip came up, putting me in Orlando during my outbound flight. Luckily, my work was kind enough to purchase a 1 way ticket to Puerto Rico from Orlando for me, I would only miss 1 day of vacation and could use my original return flight. When I called United Airlines to let them know that the outbound tickets would not be used, and they were free to do what they like with the seats, they were happy to inform me that I "must pay the $150 change fee."