In <AANLkTikhQ6NkY6A-nH=BkChhEcwMGqcmCXJHd3TyUTOj at mail.gmail.com> Larry Barber <lebarber at gmail.com> writes: >Is there some way to cancel an 'ack' after it has been issued? I guess you can re-send the ack with a very short duration-value. Regards, Henrik