I believe that most airlines will only let you change your return ticket free of charge once if you fly in on 60 day Visa exempt, then extend 30 days.Then do a border bounce.You would have to change your return flight twice
How do people handle this
TLDR : Answer Summary
Changes to return tickets and associated costs heavily depend on the airline and ticket fare category purchased. For those entering Thailand on a 60-day Visa Exempt entry and extending it, it’s crucial to understand how your chosen fare allows changes—higher fare categories typically offer more flexibility with fewer charges. Many users share their experiences of rarely needing a return ticket and suggest alternatives like purchasing a one-way ticket or managing border bounces to neighboring countries. It's emphasized that airline ticket rules vary significantly, so buying a ticket that allows for changes can save money and hassle later.