Sub Sections 2 and 4 of Section 12 provide as follows: "(2) In the case of a non residential building, where a tenant carrying on business in the building admits a person who is not a member of his family as a partner or a new partner, as the case may be, the tenant shall be deemed to have ceased to occupy the building. "(4) Any building or part which a landlord or tenant has ceased to occupy within the meaning of sub section (1), or sub section (2), or sub section (3), sub section (3 A) or sub section (3 B), shall, for the purposes of this Chapter, be deemed to be vacant," Section 13 provides that where a landlord or tenant ceases to occupy a building or part thereof, no person is to occupy it in any capacity on his behalf or otherwise than under an order of allotment or release under Section 16 Section 15 casts a duty on every landlord or tenant to give intimation of vacancy to the District Magistrate.