LEBANON — As two top leaders at Dartmouth Hitchcock Medical Center retire this fall, leadership responsibilities will be shifting.

Jeff O’Brien, DHMC’s chief operating officer, is scheduled to retire Oct. 5, and Sue Reeves, DHMC’s executive vice president, is set to retire in early November, according to a message Dartmouth Health CEO Joanne Conroy sent to staff this week.

O’Brien came to DHMC in November 2021 from the Lahey Clinic Medical Center in Burlington, Mass., where Conroy had served as CEO before coming to Dartmouth Health in 2017.

Reeves has served as DHMC’s executive vice president since July 2020. She also serves as chief nursing executive for the DH system, which in addition to DHMC includes five other hospitals, a visiting nurse organization and clinics in the Twin States. She’s been in the chief nursing role since June 2017.

Until the leadership positions at DHMC are filled, Conroy is planning to spend more time directing operations at the health system’s flagship academic medical center.

“Departures are often bittersweet but they also create opportunities for change,” she wrote.

The leadership changes come as the health care system has reported more stable finances in recent months, following the implementation of a financial improvement plan, the opening of a new patient tower and layoffs. The system still lost about $45.3 million, or 1.5%, in the fiscal year that ended June 30. But it showed a gain in the fourth quarter that ended June 30, of $47.8 million.

“There has been incredible work done throughout the organization to stabilize our finances to create stability and growth that will allow us to meet the increasing demand for our services,” Conroy wrote. “We must continue those efforts.”