His Royal Highness Crown Prince Maha Vajiralongkorn was designated heir to the throne of the Chakri dynasty as of December 28, 1972, according to the Royal Gazette published on December 28, 1972.
However, Prime Minister Prayut Chan-ocha had informed the 3 National Legislative Assembly on Thursday that the Crown Prince would like to take some time to grieve with the nation before accepting the invitation to become king.
In accordance with Section 2 of the interim constitution, the cabinet would submit the name of the heir to the throne to the NLA for acknowledgement after which the NLA president would invite the heir to ascend the throne.
During the transition period from now until the Crown Prince’s ascension to the throne, Privy Council president Prem Tinsulanonda is automatically the regent pro tempore, according to NLA vice president Peerasak Projit, citing the interim constitution.
But the duty of the regent pro tempore will come to an end once the NLA invites the heir to become the new king, according to Section 23 of the charter.
Source: Thai Public Broadcasting Service (Thai PBS)