Inter-organizational business processes usually require complex and time-consuming interactions between partners than simple interactions supported by WSDL. Automated reconciliation is essential to enable dynamic inter-organizational business collaboration. To the best of our knowledge, however, there is not a practical automated reconciliation algorithm available. In this paper, we propose a practical automated reconciliation algorithm, called IPR (Interaction Process Reconciliation) based on Petri Net, which is able to effectively facilitate dynamic interactions among trading partners in a peer-to-peer fashion. We implement a prototype IPR server in our lab, and evaluate our design by comprehensive experiments. Results show that IPR significantly outperforms existing approaches in terms of matching success rate, response time, and matching efficiency.