The Director of the Department of Revenue, while reviewing and apportioning the tentative assessment roll, may not increase the valuation of any property on the roll without giving to the company or person in whose name the property is assessed at least six days’ written notice to appear and show cause, if any, why the valuation of the assessable property of the company or person, or some part thereof, to be specified in the notice, should not be increased. A notice is not necessary if the person or company appears voluntarily before the director and is notified by the director that the property of the person or company, or some specified part thereof is, in the opinion of the director, assessed below its assessed value. [Amended by 1955 c.735 § 3; 1957 c.325 § 2; 1967 c.78 § 4; 1969 c.520 § 32; 1977 c.870 § 35; 1991 c.459 § 154; 1993 c.270 § 35; 1995 c.650 § 91; 1997 c.541 § 212; 1999 c.223 § 5; 2007 c.616 § 6]