MARBLEHEAD – A popular Marblehead High School administrator and two well-known volunteers bid farewell to their posts this month.MHS Assistant Principal Kristina Kyles is scheduled to leave next Monday to pursue the last year of her doctorate program, an intensive research phase.Kyles, a former businesswoman who became head of the town’s METCO program four years ago and was named to her present $91,000 position two years ago, is seeking a doctorate degree in education at Cambridge College."I’ll miss the people," Kyles said, "the teachers and the community.""I truly appreciate the opportunity I had in Marblehead and I will carry it with me forever.’Principal Ken Weinstein, who had advance notice of her departure, has begun interviewing candidates for her position.Former Marblehead Village School Building Committee Chairman Michael Rockett, who was elected to the Board of Selectmen last May, resigned from the committee Dec. 15.In his letter, Rockett thanked the committee for giving him the opportunity to serve the School Department on the committee that oversaw the new Marblehead High and the renovation of the Marblehead Veterans Middle School."If there’s anything you need you know how to get in touch with me," Rockett wrote.Former School Committee Chairman Amy Drinker has stepped down from the Glover School Building Committee due to other commitments. Following the announcement of her resignation, School Committee members said they would seek another community representative for that committee, possibly someone with construction experience.