The employer has to draw up a duty roster (work shift schedule) that shows the start and end times for regular working hours and daily rest periods. The duty roster usually has to be drawn up for the same period as the working hours offsetting system. Written duty rosters are created beforehand and must be made known to employees in good time, at least a week before the beginning of each roster.
The duty roster can only be altered by agreement or following a surprising change to the prerequisites for having the work carried out. Also in the last-mentioned situation, the change must be agreed on and must be made known to the employee as soon as possible. Different collective agreements have slightly different stipulations concerning duty rosters so it is worth checking the stipulations in the collective agreement that applies to you. The basic principle is that the duty roster is binding and it cannot be altered unilaterally without a justifiable reason. The employer cannot unilaterally alter the duty roster in cases where the employee has already arrived for the shift.