If an investigation shows that any part of a rule of the division of wildlife should be modified for any cause not known, fully understood, or present at the time the rule was adopted, the chief of the division of wildlife may amend any part of the rule to meet the new condition or situation, but the amended rule shall be effective not longer than one year from its effective date.

If an investigation shows that such a rule or amended rule should be rescinded for any cause not known, fully understood, or present when the rule or amended rule was adopted, or due to a change in conditions making the rule or amended rule not necessary, the chief may rescind the rule or amended rule and make it ineffective, except that if a rule or amended rule required the approval of the wildlife council for its adoption, it may be amended or rescinded only upon approval of the council.