u/AintTiredofTraveling

I currently have a J booking on BA using JAL miles and am completely fine flying J, but I have extra miles and would love to treat my partner to F if space opens closer to departure.

I know BA tends to release more F award space last minute, but from what I understand JAL only allows partner award bookings or changes up to about 72 hours before departure, as I keep getting a time stamp error for t-1 flights.

TLDR: Has anyone been able to cancel and rebook into BA F (Or any airline tbh) close to departure through JAL, or is that cutoff strict? I have also heard BA sometimes offers paid upgrades at the airport on the day of departure. Any recent experience with that? 

TIA!