Nowadays, business collaborations have to be highly dynamic and flexible to allow companies to operate efficiently and effectively in complex and volatile markets. To increase the business agility of service consumers, it is fundamental that service providers enhance the visibility of parts of their collaborative processes. Service providers are required to release both the process structures of the services offered and their status during execution. To further increase the flexibility of business collaborations, certain control over the process execution has to be offered to service consumers. In this paper, we present a framework for the support of process control in cross-organizational settings. We specify the control primitives that can be used to exert control on activities and processes before, during and after their executions. These primitives empower service consumers to postpone activity and process executions, bypass minor activities, repeat their executions, etc. We describe an approach to the support of these control primitives by service providers. We demonstrate the application of our framework with a case study from the healthcare domain. A proof-of-concept prototype implementation based on Web service technology is presented.