Conversation so far:
When did John Owen Brennan's time as a counterterrorism advisor to Obama begin?
On February 27, 2013, the Senate Intelligence Committee postponed a vote on the confirmation of Brennan. On March 5, the Intelligence Committee approved the nomination.
What led to John Owen Brennan's  appointment as counterterrorism advisor for Barack obama?
He advised Obama on foreign policy and intelligence issues during the 2008 election campaign and presidential transition.
Did John Owen Brennan have a hand in any historically significant counterterrorism?
the military operation that killed Osama bin Laden.
What military operation  that killed osama bin laden was that John Owen Brennan have a hand in?
The operation, code-named Operation Neptune Spear, was carried out in a CIA-led operation.
Did John Owen  Brennan receive any recognition or awards?

Question: When did he cease to be in that role?
Self-contained rewrite: When did John Owen Brennan  cease to be in the role of Director of the Central Intelligence Agency?