Rule 18. If any time a dealer :
(a) discontinues or sells or otherwise disposes of the whole or any part of any business carried on by him ; or 
(b) changes his place of business or any of his places of business ; or 
(c) opens a new place of business ; or 
(d) changes the name of any business carried on by him, the dealer or if he is dead, the legal representative of the deceased, shall notify the fact to the assessing authority concerned within thirty days thereafter.