Organised by IATA, the Slot Conference is held twice each year (June and November) about five months before the start of the respective schedules seasons. The conference represents approximately 100 worldwide coordinated/schedule facilitated airports and 230 airlines and will be attended by about 1200 delegates in total. During the 3 days "working conference", schedules are adjusted mainly through bilateral meetings between airlines and coordinators regarding alternatives offered, or between airlines to exchange slots offered or accepted. A schedule change at one airport must affect one or more other airports. Because usually all coordinators attend the conference, it provides the best forum in which all such repercussive changes can be quickly and efficiently processed, and airlines can leave the conference with firm schedules which they consider are the best compromise between what is wanted and what is available. The entire process is based on consensus and aims to be flexible, fair and open.