Under new rules, your employer can't change insurers without losing your health plan's exemptions from ObamaCare regulations. That is, unless a union negotiated your coverage. The administration has granted a special exception to those — and apparently only those — health care plans. A health plan is deemed "grandfathered" if it was purchased before March 23, 2010, and no major changes are made later. Such plans are exempt from most ObamaCare requirements. But new rules, officially announced Monday, make it hard to keep that status.