BPMN is suitable to model not only intra-organization workflows but also inter-organization collaborations. There has been a great effort in providing a formal semantics for BPMN, and then in building verification tools on top of this semantics. However, communication aspects are often discarded in the literature. This is an issue since BPMN has gained interest outside its original scope, e.g., for the IoT, where the configuration of communication modes plays an important role. In this paper, we propose a formal semantics for a subset of BPMN, taking into account inter-process communication and parametric verification with reference to communication modes. As opposed to transformational approaches, that map BPMN into some formal model such as transition systems or Petri nets, we give a direct formalization in First-Order Logic that is then implemented in TLA + to enable formal verification. Our approach is tool supported. The tool, as well as the TLA + theories, and experiment models are available online.