—The coordination is an essential ingredient for the mixed human-agent teamwork. It requires team members to share knowledge to establish common grounding and mutual awareness among them. In this paper, we proposed a collaborative conversational belief-desire-intention (C 2 BDI) behavioural agent architecture that allows to enhance the knowledge sharing using natural language communication between team members. We defined collaborative conversation protocols that provide proactive behaviour to agents for the coordination between team members. Furthermore, to endow the communication capabilities to C 2 BDI agent, we described the information state based approach for the natural language processing of the utterances. We have applied the proposed architecture to a real scenario in a collaborative virtual environment for training. Our solution enables the user to coordinate with other team members.