As the town refines the mission of its Emergency Medical Services advisory committee, three of what had been six committee members have quit, putting the Select Board on the search for new candidates to appoint. Undetermined as of Wednesday is when those appointments will be made and when the committee, tasked with improving Littleton’s in-house EMS and making it more cost-effective, will hold its first meeting. As of Wednesday, Littleton Town Manager Jim Gleason confirmed that residents Art Tighe, Franco Rossi and John Goodrich pulled out of the committee, leaving Scott Daine, Chad Stearns and Mike Scanlon remaining. Scanlon replied to an email from Gleason to confirm that he intends to stay on. During the Select Board’s April 11 meeting, some committee members said the committee’s mission wasn’t quite clear. The resulting confusion could be responsible for some members subsequently bowing out, said Gleason.