What happens if someone has to descend during the summit day?

If a person cannot continue ascending, one of the group's guides climbs down with that person, and the rest of the group continues ascending with the remaining guides. We do that until there is only one guide left.

If there is only one guide left, with two or more climbers, and someone has to descend, the entire group has to go down.

For safety reasons, no one can be alone on the mountain without guiding assistance.

Some private expeditions ask for one guide per person to avoid this situation (this is optional but not available for open expeditions).