 Sections 22 and 23 of the 2007 Constitution dealing with succession again relied on the Palace Law.King Bhumibol Adulyadej officially appointed Prince Vajiralongkorn, his eldest and only son, as Crown Prince and successor on 28 December 1972.The Thai constitution was amended in 1974 to allow the Privy Council to appoint a princess as successor to the throne, if the monarch had not previously appointed a successor.