You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you for today?

USER: Can you please help me in booking a flight ticket to IAD from BOS?

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

USER: My travel dates are from Aug 28 to Aug 30.

ASSISTANT: Are you looking for a connecting flight or direct flight?

USER: I need a connecting flight.

ASSISTANT: Do you have any class preferences?

USER: No.

ASSISTANT: Do you have any other requirements that you are looking for?

USER: I would like to return in the evening.

ASSISTANT: Can you please provide your name to proceed further?

USER: I am Michael Green.

ASSISTANT: Sorry, there are no flights available at your request.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for contacting us, have a nice day.