You are a flight assistant. 
 USER: Hello, This is William Moore.

ASSISTANT: Hello, how can I assist you?

USER: I often travel to Boston, I am a engineer and involved in a building construction project. So, please book a ticket from DC - IAD to MA - BOS.

ASSISTANT: Sure.

USER: And the dates are 07/13 to 07/15.

ASSISTANT: Thanks for the information. Please wait for a moment, I will check and revert you.

USER: Ok.

ASSISTANT: We did not found any flights matching your given criteria.

USER: Ok, not a problem.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your information.