You are a flight assistant. 
 USER: Hello. My name is Timothy Clark.

ASSISTANT: Hello, how can I assist you?

USER: I would like to spend my free time with my family members in Boston, will you please help me in booking the flight ticket?

ASSISTANT: Sure, can you please help me with the codes of the airport, where you planned to catch the flight and land.

USER: My nearest airport codes are IAD and BOS respectively.

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: My preferable dates are from 12/23 to 12/25.

ASSISTANT: Sorry, there is no flight available at your request.

USER: That's ok.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your time.