In recent years, flexibility has emerged as an important guiding principle in the design of business processes. However, research on process flexibility has traditionally been solely focused on ways of how the demand for process flexibility can be satisfied by advanced process modelling techniques, i.e., issues intrinsic to the process. This paper proposes to extent existing research by studying the extrinsic drivers for process flexibility, i.e. an analysis of the root causes that drive the demand for flexible processes. These drivers can be found in the context of the process, which may include among others time, location, weather, legislation, culture or performance requirements. We argue for a stronger and more explicit consideration of these contextual factors in the design and modelling of business processes. Based on a real case study, we discuss how context can be conceptualized and integrated with existing approaches to business process design. These extensions are an essential foundation for the definition and implementation of agile processes and as such of high practical and theoretical value.