Open Multiagent Systems, in which heterogeneous agents interact with each other and organize themselves into Virtual Organizations, demand infrastructures supporting these features. In these systems, dynamic and complex interactions between agents may arise. Interaction Protocols allow the definition of communication patterns. However in open systems, dynamic and complex interactions may also require these patterns be modified at execution time. We propose a support for modelling complex, concurrent and dynamic interactions between agents in terms of conversations. Conversations between agents follow predefined Interaction Protocols that can be dynamically modified without restarting the system. This support is provided at agent level and is integrated into the Magentix Multiagent Platform.