If the switch is permanent, tell the the workchart coordinator to make the appropriate changes on the job chart. When people do not show up for the jobs and have not arranged for replacements, someone asks for volunteers from the ranks and usually a cooperative soul obliges. Then the co-op's missed jobs policy kicks in and the missed jobs coordinator will track down the slacker and find a makeup job for him or her. Every semester there are two big clean-ups, usually one the weekend prior to break and one right before the end of the semester. The fun goes on continuously.
Members sign up for shifts or specific jobs.
This is the time to get at dirt that has been passed over during the rest of the semester and to make your co-op shine.