(2) Changes in the schedule may be made by posting a copy of a revised schedule in a conspicuous place in the employment agency. However, no change shall become effective until seven days after being posted in the agency. [1953 c.694 §14; 1961 c.380 §13; 1973 c.678 §12; 1981 c.318 §17; 1997 c.55 §9]