There's no charge for changing your flight booking. If the price of your hotel, car hire, transfer or experience is higher you will need to pay the difference. If the price is lower, we will refund it. Or, cancel your booking and claim a refund (incl. taxes) to the original form of payment. Call the British Airways Holidays 24-hour helpline British Airways Flight Change Policy.

https://reservationsnumber.org/flight-change/british-airways-flight-change-policy/