Wendy Sherman, the United States' lead negotiator with Iran over its nuclear program, will become acting deputy secretary of state.
The State Department announced in a November 3 statement that Sherman will continue to hold the office of under secretary of state for political affairs.
The announcement means that Sherman will hold the No. 2 and No. 3 jobs in the State Department simultaneously.
Deputy Secretary of State William J. Burns announced his decision to retire in April.
The deadline for Iran and six world powers -- the five permanent members of the UN Security Council plus Germany -- to reach a deal over its nuclear program is November 24.