Prime minister leader, the incoming leader will usually be referred as "prime minister-in-waiting". An example or this situation was in 2016 in the United Kingdom when Theresa May was elected leader of the Conservative Party while David Cameron was still prime minister. Ukraine's constitution (1996) lists the powers, functions and duties of the Prime Minister of Ukraine. Most prime ministers in parliamentary systems are not appointed for a specific term in office and in effect may remain in power through a number of elections and parliaments. For example, Margaret Thatcher was only ever appointed prime minister on "one" occasion, in 1979. She
Chief of Staff to the Prime Minister (Canada) Chief of Staff to the Prime Minister (Canada) The Chief of Staff of Canada's Prime Minister's Office is the top official of the office. The position was created in 1987 to head the PMO. Prior to the creation of the chief of staff position, the office was headed by the Prime Minister's Principal Secretary, a position which is now secondary to the chief of staff. People who held the position of principal secretary prior to 1987 were essentially "de facto" chiefs of staff, and may sometimes be informally referred to as chiefs of staff in some sources, but did not