Fountain Valley-based MemorialCare Health System said today that Steve Geidt is retiring as chief executive of Saddleback Memorial Medical Center in Laguna Hills, effective in September.

Marcia Manker, who is chief executive of sister hospital Orange Coast Memorial Medical Center in Fountain Valley, will add the CEO role at Saddleback to her duties. Manker will be leading a pair of hospitals with 470 beds and 6,400 workers between them.

The 65-year-old Geidt is a 35-year veteran of MemorialCare. MemorialCare said in a release the Laguna Niguel resident would serve on the MemorialCare Medical Foundation board after he retires.

Manker has served as Orange Coast Memorial’s chief executive since 2002. She holds degrees from California Polytechnic University-San Luis Obispo and the University of California-Davis.