How would you know how to simulate the replies in advance of the conversation (e.g., the real participant asks "what do you like to eat?" kind of thing). Or were you thinking of something simpler? Like having virtual third party who says "Please tell us your names--Player 1?" Real person types "Bob" and virtual subject types "Ed". i.e., so the questions are known in advance hence the answers can be prepared also in advance. Or something like that..!