Airline change fees vary by fare class (+1 (877) 350-???????????????? (US), route, and time of change, but in general, expect to pay a fee if you change your flight after booking, with fees ranging from $75 to $300 (1 (877) 350-???????????????? for economy fares). https://ieikm.khu.ac.kr/forums/topic/faqshow-much-is-the-penalty-for-changing-copa-airlines/