You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Michael Williams.

ASSISTANT: Michael Williams, how may I assist you today?

USER: I am looking for a flight from IAD to SFO, can you help me in booking the flight ticket from Washington?

ASSISTANT: Sure, I will help you. May I know whether you need a direct or connecting flight please?

USER: Thank you and I am looking for connecting flight, make sure that it is a evening flight for my return journey.

ASSISTANT: Thank you for letting me know, in order to proceed further I need to know your travel dates please help me with them.

USER: Sure, my planned travel dates are May 18 and May 20.

ASSISTANT: I am sorry to inform you that there are no flights available.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us. Have a great day.