Washington CNN  — 

Jennifer Williams, the special adviser to Vice President Pence on Europe and Russia who testified during the House impeachment inquiry last year, is leaving the Vice President’s office two months ahead of her planned departure at the end of March, a White House official told CNN.

Williams is a detailee to Pence’s staff from the State Department and is heading back to start another assignment as a deputy foreign policy adviser at US Central Command which oversees US troops in the Middle East and Central Asia..

She’s had the assignment lined up since last fall, the official said, and she’s leaving the Vice President’s office early to do some training before heading to Tampa where CENTCOM is based. Her last day on Pence’s staff is Monday.

The official did not dispute that Williams’ role in the Ukraine saga influenced her early departure.

However, the vice president’s office said Pence was still evaluating her request.

“Jennifer Williams, a State Department employee detailed to the Vice President’s office, requested in writing an early departure. Ms. Williams’ original scheduled departure date was the end of March. The Office of the Vice President is evaluating her request,” said Marc Short, Pence’s chief of staff.

Williams was on the July 25 call between President Donald Trump and Ukraine President Volodymyr Zelensky, and she was concerned about what she heard on the call but there is no indication Williams raised her concerns to her superiors, a source previously told CNN.

She told House impeachment investigators last November that Trump’s request for specific investigations struck her as “unusual and inappropriate” and “shed some light on possible other motivations” for his decision to freeze security aid to Ukraine.

Williams said that she had limited information about why military aid was being withheld. She was puzzled about it, but was kept in the dark about the decision-making process. She described herself as someone who stayed in her lane and wasn’t pushing to understand why the aide was withheld.

After her closed-door testimony was released, Trump attacked Williams on Twitter, characterizing her – without evidence – as a “Never Trumper.” Notably, Pence’s office declined to defend her from the attack. “Jennifer is a State Department employee,” Pence’s press secretary Katie Waldman said at the time.

Before Williams joined Pence’s staff, she was a spokesperson for several years at the US embassy in London, according to her LinkedIn profile. She also held posts at the embassies in Beirut, Lebanon, and Kingston, Jamaica.

Current and former colleagues have heaped praise on Williams, with one White House official saying: “She is the most professional person in this building.”

“Jen is the type of person who I know to be dedicated to the institution above anything else,” said Brett Bruen, the former director of global engagement at the White House under President Barack Obama.

She comes from the cadre of diplomats “who are not going to be easily intimidated or hold back information,” Bruen added. “She is someone who is pretty tough and has had tough assignments that have steeled her to the kind of pressure and the intimidation tactics that have been used against others.”

This story has been updated with additional information Thursday.

CNN’s Paul LeBlanc contributed to this report.