You can cancel a Carnival cruise without penalty if it's done within the risk-free cancellation window, usually 24-48 hours after booking. After that, fees may apply based on the Carnival cruise cancellation policy. To cancel a Carnival cruise online or learn how to cancel a Carnival cruise, call 1-888-653-0010 (OTA) for assistance. https://www.forum-joyingauto.com/showthread.php?tid=210143