The services of the church are properly conducted each day following a rigid, but constantly changing annual schedule (i.e., parts of the service remain the same while others change depending on the day of the year). Services are conducted in the church and involve both the clergy and faithful. Services cannot properly be conducted by a single person, but must have at least one other person present (i.e. a Priest cannot celebrate alone, but must have at least a Chanter present and participating). Usually, all of the services are conducted on a daily basis only in monasteries and cathedrals, while parish churches might only do the services on the weekend and major feast days. On certain Great Feasts (and, according to some traditions, every Sunday) a special All-Night Vigil (Agrypnia) will