In the Internet of Services companies work together using interorganizational business processes. These business processes represent not only long-term business relationships, but also ad-hoc collaborations. Every such cooperation calls for specific adjustments of the process. Implementing these adaptions by hand is too expensive. Therefore, a need for fast adaptability of interorganizational business processes arises. This paper presents a concept for process variants in interorganizational service networks. To accomplish this, the Business Process Modeling Notation 2.0 is extended to allow for two new kinds of diagrams: Process templates serve as customizable templates for variable processes, in which process fragments are inserted to create a specific process variant. Furthermore concepts for variable attributes of modeling elements, dependency modeling between variable process parts as well as for creating a variant from a process template are introduced. An existing variability concept is used to model variability and save it in a separate file. These concepts are implemented using the web-based editor Oryx. Finally, possible future work like validation, compliance, simulation and optimization is outlined.