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
Acting prime minister to an outgoing Prime Minister following an electoral defeat, and who by convention does not implement new policies or an interim Prime Minister who is appointed to perform a similar role to a caretaker Prime Minister, but who is typically not a Prime Minister at the time of being appointed. Within a Commonwealth nation, the office of Acting Prime Minister, like that of Prime Minister is found only in convention, and is not legislated. The Department of Prime Minister and Cabinet, or an equivalent ministry, drafts, reviews and publishes any formal conventions (though these are expressly non binding in a