You can change KLM Airlines flight date, departure, or destination online based on your ticket type, with standard ticket fees starting from €70.

To change Air Canada flight, you can modify it online up to 2 hours before departure with fees starting at $100 depending on your ticket type.

You can change your JetBlue flight online or by calling. Changes are easiest with non-Basic fares—Blue Basic has strict no-change rules, while others may incur a $25 fee if changed offline.

You can change Southwest Airlines flight up to 10 minutes before departure online or by calling without a fee, although fare differences may apply.

You can change Delta Airlines flight for a fee ranging from $0 to $400 for non-refundable tickets, while refundable tickets can get changed without a fee, but you must pay any fare difference.

American Airlines allows changes within 24 hours for a full refund if booked 2+ days before departure.