Final answer:
The best next step is to tell the client to schedule an appointment with their Primary Care Physician to get a referral for a social worker, as required by most HMO plans.
Step-by-step explanation:
In the context of a Health Maintenance Organization (HMO), the appropriate step for managing healthcare referrals is typically through a Primary Care Physician (PCP). Since HMO plans often require referrals in order to see specialists or other healthcare providers like social workers, it is important to follow the proper procedural steps to ensure the referral will be covered under the client's health plan.
Therefore, the best next step would be option 2: Tell your client to make an appointment with their PCP for the referral to the social worker. The PCP can provide a referral after assessing the client's health status and determining the necessity of specialized care. This step is crucial within the HMO structure to obtain authorization for services by the social worker, and to ensure that the client's insurance will cover the visit.