Reply To: How long do you have to accept a change by BA?

[JDB]

@Iranicus – per the EC261 Interpretative Guidelines, there is no official time limit but an airline is entitled to cancel your booking for a refund if they have notified the passenger of a change to which that passenger hasn’t responded. BA seems very relaxed about this compared to other airlines, but it doesn’t always help to play games/play chicken on this! Your booking is probably in a ‘pending’ state awaiting your decision.

You might get away with it, but nobody could sensibly advise you to leave it to the last minute as your optionality could disappear without notice.