Originally Posted by KARFA

First thing is to split the booking so you have a separate booking for each of you. You can then change or cancel your wife's booking as you wish.

For an avios booking if you cancel anytime up to 24 hours before the first flight you will get everything refunded minus a £35 per person cancellation fee deducted from the cash part. You can also change it to any date where there is reward availability, again a fee of £35 per person is payable. It may be worth you speaking to BA if this change is due to covid as I think they may have a policy in place still which might give you some extra flexibility.