Inter-organizational B2B systems are most likely tending to change their business requirements over time - e.g. establishing new partnerships or change existing ones. The problem is that business analysts design the business processes from scratch, disregarding the economic drivers of the business network. We propose to use business modeling techniques - such as REA (Resource-Event-Agents) - to ensure that business processes beneath do not violate the domain rules, i.e. to ful ll the basic economic principle for every business transaction - the give-andtake convention, called economic reciprocity. This helps us to quickly adapt the B2B processes to changing requirements without the need to change the overall architecture. In this paper we provide a mapping from REA, which represents one of the most prominent ontologies for business modeling, to UMM (UN/CEFACT’s Modeling Methodology), a standardized methodology for modeling the global choreography of interorganizational business processes. We formalize the mapping by the use of the model-to-model transformation language ATL (Atlas Transformation Language).