When you are a patient in a Skilled Nursing Facility (SNF), Home Health Agency (HHA), or Comprehensive Outpatient Rehabilitation Facility (CORF), you have the right to get all the SNF, HHA or CORF care covered by the Plan that is necessary to diagnose and treat your illness or injury. The day we end coverage for your SNF, HHA or CORF services is based on when these services are no longer medically necessary. This part explains what to do if you believe that coverage for your services is ending too soon.