Anna Burger, a top labor leader at the SEIU and Change to Win, will leave that position, according to an official.

Burger will retire from her positions as secretary-treasurer at the Service Employees International Union (SEIU) and chairwoman of the Change to Win coalition, marking an era of major transition for the powerful union.

Her departure comes after she lost the election to replace Andy Stern as the top leader of the SEIU earlier this year, leaving Mary Kay Henry as the union's new president.

SEIU has been one of the biggest boosters of President Obama's agenda, helping push through a number of legislative priorities and spending big on behalf of Democratic candidates.

Henry will fill Burger's responsibilities temporarily until a September vote can be held on a successor.

It's not clear what Burger will do next, though she vowed to remain politically active.

"As excited as I am about the election of Barack ObamaBarack Hussein ObamaAfter Dems stood against Pompeo, Senate’s confirmation process needs a revamp ‘Morning Joe’ host: Trump tweeting during Barbara Bush funeral ‘insulting’ to US Trump and Macron: Two loud presidents, in different ways MORE president, I am committed to building a permanent and sustained progressive majority. The challenges we inherited from the Bush administration aren’t going away any time soon," she said. "We need to put America back to work and continue to take on the excess of Wall Street and corporate greed. But it’s not enough to just fix it — we need to return America to a country that works for all of us. We need a strong and coordinated progressive infrastructure that protects our American values of fairness and justice, and I intend to be part of that work."