Section 418. Assignment of mortgage, lease, or other lien or charge

The
  holder of any mortgage, lease, or other lien  or  charge  on  registered
  property,  in  order  to  transfer  the  same or any part thereof, shall
  execute an assignment of the whole or any part thereof;  and  upon  such
  assignment  being  filed  in  the office of the registrar, the registrar
  shall enter in the title  book  a  memorial  of  such  transfer  with  a
  reference  to the assignment by its file number; he shall also note upon
  the instrument on file in his office intended  to  be  transferred,  and
  upon   the  registration  copy  thereof  produced,  the  number  of  the
  certificate on which the memorial is  entered,  with  the  date  of  the
  entry.