6 Section 17. In the case where the King does not appoint a Regent under section 16 or is unable to appoint a Regent owing to His not being sui juris or any other reason, but the Privy Council is of the opinion that it is necessary to appoint a Regent and is unable to inform the King to make an appointment in due course, the Privy Council shall propose the name of one person or several persons forming a council sequentially from those determined in advance by the King to be Regent and notify the President of the National Assembly to make an announcement, in the name of the King, to appoint such person as Regent. Section 18. While there is no Regent under section 17, the President of the Privy Council shall be Regent pro tempore. In the case where the Regent appointed under section 16 or section 17 is unable to perform his or her duties, the President of the Privy Council shall act as Regent pro tempore. While being Regent under paragraph one or acting as Regent under paragraph two, the President of the Privy Council shall not perform his or her duties as President of the Privy Council. In such case, the Privy Council shall elect one Privy Councillor to act as President of the Privy Council pro tempore. Section 19. Before taking office, the Regent appointed under section 16 or section 17 shall make a solemn declaration before the National Assembly in the following words: “ I, (name of the declarer), do solemnly declare that I will be loyal to His Majesty the King (name of the King) and will faithfully perform duties in the interests of the country and the people. I will also uphold and observe the Constitution of the Kingdom of Thailand in every respect.” A Regent who has previously been appointed and made the solemn declaration need not make the solemn declaration again. Section 20. Subject to section 21, the succession to the Throne shall be in accordance with the Palace Law on Succession, B.E. 2467 (1924). An amendment to the Palace Law on Succession, B. E. 2467 ( 1924) shall specifically be the Royal Prerogative of the King. At the initiative of the King, the Privy Council shall prepare the draft Palace Law Amendment to the existing Palace Law and shall present it to the King for His consideration. When the King has already approved the draft Palace Law Amendment and bestowed His signature thereon, the President of the Privy Council shall notify the President of the National Assembly who shall inform the National Assembly. The President of the National Assembly shall countersign the Royal Command.