Exceptions are the events or situations that prevent business processes from completing normally. When exceptions such as cancellation of customer order occur, additional time and resources are often needed to resolve them. It is important for enterprise to pay attention to exceptions, for reducing exceptions efficiently and effectively may trace business process oriented improvement or innovation. In this study, a conceptual level pattern for reducing exceptions is proposed and discussed. This study contributes to research by 1) understanding how DEMO can help to reduce exceptions and improve business process flexibility through a case study of a Japanese company; 2) discussing suggestions for reducing exceptions and improving business process flexibility in general, 3) analyzing reasons of exceptions generating in the context of business model change from production centered to customer-centered, and how DEMO could help to enhance this change.