North Carolina’s Medicaid recipients now can decide which health plan they’ll use for medical services when a system overhaul goes online July 1. Open enrollment for Medicaid managed care began this week and ends May 14. About 1.8 million people covered by Medicaid or a related program should enroll and choose from one of several plans. People who don’t will be placed in a plan automatically. The state is switching from a traditional fee-for-service program to one in which health plans receive fixed monthly payments for every patient treated. Managed care supporters believe it will control expenses and result in healthier patients.