White House chief of staff John Kelly waits for President Donald Trump to give a press conference on September 26, 2018, in New York City.
Kelly reportedly intervened to stop Trump firing Department of Homeland Security Secretary Kirstjen Nielsen last month. McGahn had refused to publicly deny the reporting.
Ayers, Vice President Mike Pence's chief of staff, has emerged as the clear favorite to replace Kelly.
Kelly and Trump have grown tired of each other.
Missing tourist: 'The longer this goes on, the more worrying it is'
Millane is said to have been in New Zealand for about two weeks, and was staying at a backpackers' hostel in Auckland city centre. Detectives are investigating the disappearance of 22-year-old Grace Millane , who was last seen in Auckland on Saturday night.
But reports that Kelly and Trump are no longer speaking are overblown, the people said. Kelly started holding increasingly fewer senior staff meetings - once daily occurrences were whittled down to weekly gatherings - and began to exert less control over who talks to the President. Kelly's shifting accounts caused his credibility inside the West Wing to plummet, and it never truly recovered, according to officials.
Like all of those interviewed, the person spoke on condition of anonymity to discuss sensitive personnel matters.
Trump often vacillated between criticizing and praising Kelly, sometimes within minutes of each other.
Barr, who also worked as AG for former President George HW Bush, replaces Jeff Sessions.
"Now is the best opportunity to be laser-focused on further building out the political infrastructure that will support victory for President Trump and the GOP in 2020", campaign manager Brad Parscale said in a statement. Add Trump Administration as an interest to stay up to date on the latest Trump Administration news, video, and analysis from ABC News.
Barr is likely to face tough questions at his confirmation hearing about how he will handle the ongoing special counsel investigation into possible coordination between the Trump campaign and Russian Federation to influence the 2016 presidential election.