RICARDO ALONSO-ZALDIVAR, Associated Press

WASHINGTON (AP) — Medicare chief Marilyn Tavenner — who oversaw the rocky rollout of the president’s health care law — says she’s stepping down at the end of February.

In an email Friday to staff at the Centers for Medicare and Medicaid Services, Tavenner says she’s leaving with “sadness and mixed emotions.”

Tavenner survived the 2013 technology meltdown of HealthCare.gov, but was embarrassed last fall when she testified to Congress that 7.3 million people were enrolled for coverage. That turned out to be an overcount that exaggerated the total by about 400,000.

Calling Tavenner “one of our most esteemed and accomplished colleagues,” Health and Human Services Secrerary Sylvia M. Burwell said the decision to leave was Tavenner’s.

Principal deputy administrator Andy Slavitt will take over as acting administrator.