Section 28-102.4.2. Change in use or occupancy

Except as otherwise provided
  in sections 28-101.4.1, 28-101.4.2, 28-101.4.3 or 28-101.4.4 changes  in
  the  use  or  occupancy  of  any  building  or  structure made after the
  effective date of this code shall comply with  the  provisions  of  this
  code.  Any  changes  made  in  the  use  or  occupancy  of a building or
  structure not in compliance with this code shall be prohibited and shall
  be a violation of this code. After a change in use or occupancy has been
  made in a building, the re-establishment of a  prior  use  or  occupancy
  that  would  not  be  lawful  in a new building of the same construction
  class shall be prohibited unless and until all the applicable provisions
  of this code and other applicable laws and rules for such  reestablished
  use  or  occupancy  shall  have  been complied with. A change from a use
  prohibited by the provisions of this code, but which was permitted prior
  to the effective date of this code, to another  use  prohibited  by  the
  provisions of this code shall be deemed a violation of this code.