American Carnage: On the Front Lines of the Republican Civil War and the Rise of President Trump by Tim Alberta:
Some of the president-elect's appointments were products of patronage. Back in January 2016, South Carolina's lieutenant governor, Henry McMaster, became the first statewide official in any of the three early-nominating states to endorse Trump. McMaster went all in, traveling with the campaign and becoming close to the future president, never wavering in his support. A few days after the election, Trump called McMaster and said, "Henry, what do you want? Name it."
McMaster told him he wanted to be governor.
"That's it?" Trump replied. "Well, that should be easy. You're already the lieutenant governor!"
McMaster explained that it wasn't that simple. Elections were uncertain things. The only way to ensure his promotion would be for Nikki Haley to go away. Within days, seemingly out of left field, Trump announced Haley as his pick for ambassador to the United Nations. McMaster was sworn in on January 24.