legislative approval by reenactment

The oft-repeated statement that administrative construction receives legislative approval by reenactment of a statutory provision, without material change, covers the situation where the validity of administrative action standing by itself may be dubious or where ambiguities in a statute or rules are resolved by reference to administrative practice prior to reenactment of a statute; and where it does not appear that the rule or practice has been changed by the administrative agency through exercise of its continuing rule-making power. It does not mean that a regulation interpreting a provision of one act becomes frozen into another act merely by reenactment of that provision, so that that administrative interpretation cannot be changed prospectively through exercise of appropriate rule-making powers.