Section 6
SEC. 6. After final decree has been entered for the registration of a lot its cadastral number shall not be changed except by order of the Court of Land Registration. Future subdivisions of any lot shall, with the approval of said court, be designated by a letter or letters of the alphabet added to the cadastral number of the lot to which the respective subdivisions pertain. The letter with which a subdivision is designated shall be known as its "cadastral letter:" Provided, however, That subdivisions to cities or townsites may, with the approval of the court, be designated by block and lot numbers instead of cadastral numbers and letters. All subdivisions under this section shall be made in accordance with the provisions of section forty-four of Act Numbered Four hundred and ninety-six, and the provisions of section fifty-eight of the said Act shall be applicable to conveyances of lands so subdivided.