According to a White House insider, Tina Flournoy, Vice President Kamala Harris’ chief of staff, is departing the Biden administration, the latest in a string of Harris staff departures that began amid rumors of upheaval in the vice president’s office.

Lorraine Voles, a Harris senior advisor and former communications director for Vice President Al Gore and Hillary Clinton, will succeed Flournoy, who has held the position since Harris took office.

Traveling reporters were unable to reach Harris, who was in her hometown of San Francisco on Thursday to discuss maternal health, for comment on Flournoy’s departure.

Symone Sanders, Harris’s primary spokeswoman and senior advisor, quit at the end of last year and will shortly headline a television show on MSNBC. As part of a bigger communications makeover, Harris’ communications director Ashley Etienne stepped down and was replaced by Democratic communications staffer Jamal Simmons.

To explain the exits, the White House cited the roles’ arduous and taxing nature. Last year, there were complaints of irritation and disarray in the vice president’s office, according to insiders. The government reacted harshly to the news.

Harris, the first female vice president and the first Black and South Asian American to hold the position, has come under fire for her handling of difficult subjects such as addressing the core causes of immigration, voting rights, and abortion access.

Flournoy formerly worked as Bill Clinton’s chief of staff and for Al Gore’s presidential campaign and the Democratic National Committee in different capacities.

Her departure comes as the White House and Democrats face significant challenges in keeping control of the Senate and House in the upcoming midterm elections, which are less than seven months away.

Flournoy has been a key component of the White House team since the outset, according to White House chief of staff Ron Klain: “Her experience, wisdom, and hard work have been instrumental to our success on many issues.”