 However, if the non-residential tenement was occupied before the issue of the relevant document, the effective date is the date of occupation.In this context, a relevant document means an Occupation Permit issued by the Building Authority, a Certificate of Compliance issued by the Director of Lands or a document signed by the Director of Housing certifying completion of a building erected by the Hong Kong Housing Authority.The effective date of a correction shall, in the case of a correction of misdescription or clerical or arithmetical error, be the date specified in the notice and in the case of a correction resulting from a change of building number or street name, shall be the effective date of the change.