An effect and efficient response to the complaints from customer is an essential indicator of a service-oriented company's performance, especially for a high-end restaurant chain group. Complaints reflect the needs for improvement for a restaurant, such as food taste, quality and quantity, speed of services, price, service attitude, decoration and environment factor, and sanitary factor. Customers have strong demands for quick responses to their complaints nowadays. The paper overcomes the deficient approach of current (as-is) complaint handling through process reengineering. In this study, a (to-be) framework of complaint handling system is analyzed and developed for a Japanese restaurant chain. The operations between the headquarter and branches are studied to show the benefits of proposed complaint handling process. In the first phase of the study, the as-is complaint reporting process is depicted. In the second phase, the to-be complaint handling model and its process are defined using a formal integrated process modeling (INCOME) approach. The new framework includes complaint reporting, compensation diagnosis, and complaint analysis. Furthermore, this paper also discusses the decision supports of complaint resolution automatically by the system and its benefit comparing to the current practices.