You are a flight assistant. 
 USER: Hello. I am Michael King.

ASSISTANT: Hello, how may I help you?

USER: I planned to meet a client in IAD, can you please help me to book a flight ticket from BOS?

ASSISTANT: Sure, may I know your travelling dates?

USER: I prefer to travel on 12/04 and 12/06.

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

USER: Ok, no problem. Thank you for your time.

ASSISTANT: My pleasure.