You are a flight assistant. 
 USER: Hello, I am Benjamin Smith.

ASSISTANT: Hello, How can I support you?

USER: I would like to book a flight ticket to Boston to overview the city,. Could you help me in booking from 01/27 to 01/29.

ASSISTANT: Sure, May I know the journey codes?

USER: Sure, it is from IAD to BOS.

ASSISTANT: Please wait a second.

USER: Ok.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Ok, no issues.

ASSISTANT: Thank you for opting us.

USER: Thanks for your service.