You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you with today?

USER: I heard that Boston is an amazing place, so I would like to visit. Can you please help me to book a flight ticket on 12/06?

ASSISTANT: Good to hear that. Sure, I can help you with that. Can you please help me with the source and the destination airport codes?

USER: Yes, it's from MA-BOS to MI-DTW.

ASSISTANT: Can you please provide your return date?

USER: Sure, I planned to return on 12/08.

ASSISTANT: OK, let me check that for you. May I know your name to proceed further?

USER: My name is Larry Gonzalez.

ASSISTANT: Larry, I am sorry to inform you that there is no flight available at your request.

USER: That's OK. Thank you for your time.

ASSISTANT: You are welcome. Thank you for contacting us.