The US ambassador to the UN Nikki Haley has announced her intention to resign, and Donald Trump has ruled out that she’ll be replaced by his daughter Ivanka.
In a tweet on Tuesday evening, Ms Trump, presidential senior adviser and the US president's eldest daughter, said her father will "nominate a formidable replacement for Ambassador Haley".
She adds: "That replacement will not be me."
Trump told reporters that selecting his daughter would spark concerns about nepotism.
But he also said there is no one more competent in the world for the role than Ivanka.
The post requires confirmation from the US Senate.
'I'm not running in 2020'
Ms Haley hinted in her resignation letter to Mr Trump that she is seeking a job in the private sector and ruled herself out of running for president in 2020.
"I have given everything I've got these last eight years," she said, referring to her six years as South Carolina governor as well as her time at the UN.
"And I do think it's good to rotate in other people who can put that same energy and power into it."
There has been speculation that Ms Haley, the former governor of South Carolina, will return to government or politics at some point.
"No, I'm not running in 2020" she joked, quickly adding that she would be supporting Trump.
The decision to announce the latest shake-up came less than a month before the congressional elections, even as the White House has made a concerted effort to hold off on major changes - at the Justice Department and elsewhere - before then.
Trump was asked why the announcement was made now since Ms Haley is staying until the end of the year.
Instead of answering directly, he recounted how she has had to work on tough issues, such as Iran and North Korea.
White House officials had sought to put a hold on record-setting administration turnover in the run-up to the November 6 elections, with aides being asked months ago to step down or commit to stay to election day to avoid adding to a sense of turmoil.
A number of high-profile staff have resigned or been dismissed since Trump took office.
Trump said Ms Haley first discussed leaving the administration with him six months ago.
The timeline also coincides with a high-profile spat between Ms Haley and the White House in April, when she drew the president's ire for previewing in a television appearance the administration's planned imposition of a new round of sanctions on Russia.
When the sanctions never materialised, White House officials said the plans had changed without Ms Haley being briefed, and top economic adviser Larry Kudlow suggested Ms Haley was confused.
"I don't get confused," Ms Haley said in a sharply-worded rebuke to the West Wing.