Aer Lingus permits flight date changes up to two hours before departure, subject to fare type and availability. Changes may incur a fee plus any fare difference. Saver and Plus fares are changeable online for a fee, while Advantage, Aer Space, and Flex fares allow changes without a fee, though fare differences apply. To make changes, visit Manage My Booking or call +1 (877)-310-4366. https://americanairtravel.com/aer-lingus-flight-date-change-policy/