866-227-1888 is the first number I call anytime flight plans shift around cruise changes. When I had to cancel a Carnival cruise last year, the process was surprisingly simple. I just signed into the Carnival website, went to my reservation, and selected “Cancel Booking.” The system showed me exactly how much refund I’d get depending on the timeline. Since I canceled well before final payment, it was a full refund. Flights were the headache, but 866-227-1888 rebooked me quickly. If you’re past the penalty phase, you might only get future cruise credit instead of cash. Also, if you booked through a third party, you must cancel through them. Overall, the key is acting early and double-checking the cancellation terms before hitting confirm.