(2) Equivalent procedures must demonstrably meet the requirements in Volume IV of Annex 16  to the Chicago Convention.  15. —(1) The CAA must provide such assistance and advice as a Regulator may require in  connection with any of the Regulator’s functions under this Order.  (2) The CAA is entitled to recover from the Regulator a sum equal to any expense reasonably  incurred by it in providing the Regulator with assistance or advice under paragraph (1).  16. —(1) Where—  this new State must become the State to which the aeroplane operator fulfils its requirements  under Volume IV of Annex 16 to the Chicago Convention from the start of the next compliance  period.  (2) The aeroplane operator must notify the Regulator of any change described in paragraph (1)  within 3 months of the change taking effect.  (3) An aeroplane operator with a wholly owned subsidiary aeroplane operator that has its  registered office in the United Kingdom can be treated as a single consolidated aeroplane operator  liable for compliance with the requirements of Volume IV of Annex 16 to the Chicago  Convention, subject to the approval of the Regulator. Evidence must be provided in the aeroplane  operator’s Emissions Monitoring Plan to demonstrate that the subsidiary aeroplane operator is  wholly owned.  17. —(1) Where—  R is the Regulator of that aeroplane operator from the beginning of the next compliance period.  (2) Where—  S is the Regulator of that aeroplane operator from the beginning of the next compliance period.  (3) The aeroplane operator must notify the Regulator of any change described in paragraphs (1)  and (2) within 3 months of the change taking effect.  11 (b) at the end of that scheme year that registered office or place of residence is in the area of  a Regulator (“S”),  (a) an aeroplane operator which did not have a registered office or place of residence in the  United Kingdom at the beginning of a scheme year acquires a registered office or place or  residence in the United Kingdom in the course of that period, and  (b) that aeroplane operator’s registered office or place of residence is in the area of R at the  end of the scheme year,  (a) an aeroplane operator attributed to the United Kingdom under article 8(1) with a  registered office or place of residence in the area of a Regulator, in a scheme year,  changes the address of its registered office or place of residence to the area of a different  Regulator (“R”), and  Change in aeroplane operator’s registered office within the United Kingdom  Change in aeroplane operator’s attribution to a State Aeroplane operator’s change in circumstances  CHAPTER 2  The CAA  (a) an aeroplane operator changes its ICAO Designator, air operator certificate or equivalent,  or place of its registered office, and is subsequently attributed to a new State in  accordance with paragraph 1.2 of Chapter 1, Part II, Volume IV of Annex 16 to the  Chicago Convention, but  (b) that aeroplane operator is not establishing a new entity or a subsidiary, 