Change cash booking to avios booking

[spoonfork]

Hi,

I have a cash booking for myself and wife from LGW to MCO in Economy in a few weeks. I have seen there is now reward availability in CW on the same day and have some Barclays vouchers to use. would BA let me change the return flight cash booking to a one way reward flight? I know the cash fare is not refundable, but wondered if they would let me use the cash fair to pay the taxes on the reward booking?

if this is a stupid question and is covered elsewhere, apologies.

[roger]

When did you book your cash flight? If within 24 hours and booked directly with BA, you can do this, otherwise it is probably not worth it.

[spoonfork]

months ago.

ok I thought as much. cheers