You are able to modify your flight before to departure with Aer Lingus's flight modification policy. In accordance with the terms and conditions, you will be responsible for the charge difference if you purchase an expensive ticket after selecting a less expensive flight. You can contact customer support by phone, on the Aer Lingus website, or by using the live chat feature to change your flight. When booking your tickets, make sure everything is correct because Aer Lingus may charge you more if you decide to change your schedule after 24 hours.
https://flightcancellationpoli....cy.com/aer-lingus-fl

If your Air New Zealand flight is cancelled within 24 hours of booking and if you purchase a flight one week before departure, this airline will provide a full refund. As per the Air New Zealand flight cancellation policy, you will have to pay cancellation charges, which depend on your fare type. If you cancel your ticket for whatever reason and it is refundable, the airline will credit your bank account with a full refund.
https://flightcancellationpoli....cy.com/air-new-zeala

You shouldn't worry if your plans suddenly change and you can't continue traveling with Volaris Airlines! You can cancel your flight according to Volaris Airlines' cancellation policy. Terms and conditions apply to the cancelation of the Volaris flight.
https://flightcancellationpoli....cy.com/volaris-airli

Aer Lingus baggage allowance policy allows you to bring one small cabin bag and one personal items, without incurring the extra charges. The baggage allowances are subject to certain terms & conditions. If your carry-on baggage size is more than the maximum limit, you will be responsible for additional costs. You may purchase the additional luggage,when you make a reservation with Aer Lingus.
https://flightcancellationpoli....cy.com/aer-lingus-ba