A data management system for managing appointment and payment transactions, such as HIPAA transactions, for patient care is provided. The data management system operates within a network of medical service entities and insurance entities that communicate with one another via standardized transactions. The system receives an eligibility-benefits transaction related to a patient and constructs a corresponding confirmation transaction that indicates the patient's eligibility status. The system further receives a payment request transaction and constructs a corresponding payment transaction that includes information related to payment authorization and processing of an amount due. The system automatically receives the transactions based upon a registration with a medical service entity as a payer for the patient. The data management system thus emulates an insurance company to process appointment scheduling and payment information and to communicate the information to the medical entity.