Mark Sandy, a longtime career employee at the White House Office of Management and Budget, is expected to appear to testify to Democrats’ impeachment inquiry on Saturday - The Washington Post

A longtime career employee at the White House Office of Management and Budget is expected to break ranks and testify Saturday in the House Democrats’ impeachment inquiry, potentially filling in important details on the holdup of military aid to Ukraine.
https://www.washingtonpost.com/us-policy/2019/11/14/career-white-house-budget-official-expected-break-ranks-testify-impeachment-inquiry/