If the unauthorized building works have been completed, can I seek approval from the Buildings Department so that the UBW can become legal?

Under section 42(5) of the Buildings Ordinance, the Building Authority is not empowered to approve building works which is already completed.  Therefore, property owner cannot apply for approval from the Buildings Department (BD) to carry out building alteration works after the works is completed to make the unauthorized building works (UBW) become legal.  Property owner must remove UBW first and then appoint an Authorized Person to prepare and submit plans for the approval of BD.  Property owner can commence the concerned works after the plan is approved by BD.