7 The Palace Law Amendment shall have force of law upon its publication in the Government Gazette. Section 21. In the case where the Throne becomes vacant and the King has already appointed an Heir to the Throne under the Palace Law on Succession, B.E. 2467 (1924), the Council of Ministers shall notify the President of the National Assembly. The President of the National Assembly shall convoke the National Assembly for acknowledgement thereof, and shall invite such Heir to ascend the Throne and proclaim such Heir as King. In the case where the Throne becomes vacant and the King has not appointed an Heir under paragraph one, the Privy Council shall submit the name of the Successor to the Throne under section 20 to the Council of Ministers for further submission to the National Assembly for approval. In this regard, the name of a Princess may be submitted. Upon the approval of the National Assembly, the President of the National Assembly shall invite such Successor to ascend the Throne and proclaim such Successor as King. Section 22. Pending the proclamation of the name of the Heir or the Successor to the Throne under section 21, the President of the Privy Council shall be Regent pro tempore. However, if the Throne becomes vacant while a Regent has been appointed under section 16 or section 17 or while the President of the Privy Council is the Regent under section 18 paragraph one, such Regent, as the case may be, shall continue to be the Regent until the proclamation of the name of the Heir or the Successor to ascend the Throne as King. In the case where the Regent who has been appointed and continues to be the Regent under paragraph one is unable to perform his or her duties, the President of the Privy Council shall act as Regent pro tempore. In the case where the President of the Privy Council is the Regent under paragraph one or acts as the Regent pro tempore under paragraph two, the provisions of section 18 paragraph three shall apply. Section 23. In the case where the Privy Council has to perform its duties under section 17 or section 21 paragraph two, or the President of the Privy Council has to be or act as Regent under section 18 paragraph one or paragraph two or section 22 paragraph two, and there is, during that period, no President of the Privy Council or the President of the Privy Council is unable to perform duties, the remaining Privy Councillors shall elect one among themselves to act as the President of the Privy Council or to be or to act as Regent under section 18 paragraph one or paragraph two or section 22 paragraph two, as the case may be.