Business service engagements involve processes that extend across two or more autonomous organizations. Because of regulatory and competitive reasons, requirements for cross-organizational business processes often evolve in subtle ways. The changes may concern the business transactions supported by a process, the organizational structure of the parties participating in the process, or the contextual policies that apply to the process. Current business process modeling approaches handle such changes in an ad hoc manner, and lack a principled means for determining what needs to be changed and where. Cross-organizational settings exacerbate the shortcomings of traditional approaches because changes in one organization can potentially affect the workings of another.