Flournoy is slated to be replaced by Lorraine Voles, the veteran Democratic communications strategist who joined Harris' office as an adviser last summer.  

Voles would focus her efforts on "organizational development, strategic communications and long-term planning," an official told CNN at the time. 

In an email to staff obtained by CNN, Flournoy said she was "eternally grateful to the vice president for giving me this amazing opportunity," and thanked the staff.

"It had been my intention to speak to all of you individually to let you know that I will soon be leaving the Vice President's Office and my role as Chief of Staff," she wrote 

"I will, however, be talking to you in the coming days. I will say then -- in much more poetic language, no doubt 

that it has been an honor to work for the Vice President and a great joy to get to know Kamala Harris and see first hand the great passion she brings to her job." 

Flournoy is the latest in a long string of departures from the vice president's office, which has been shaken up multiple times in recent months. 

Flournoy's deputy Michael Fuchs earlier this month announced that he would be leaving the administration.