there is a rebooking allowance for this for any of BUR,LAX,ONT,SNA where your flight is still running.

for any tickets issued by 9 JAN 2025, and for travel from 8 JAN 2025 to 15 JAN 2025, you can rebook to other flights in the period from 08 JAN 2025 to 20 JAN 2025.

BA will rebook into the same class as the original flight or lowest available in the same cabin. No origin/destination/stopover changes are permitted. Refunds are not allowed, unless provided for based on the fare. Reward bookings are included.

Other than the above, anything else you want to do would be in accordance with your fare rules i am afraid.