You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Timothy Davis. I want to book a ticket from IAD to ATL, can you help me?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travel dates are 11/07 and 11/09.

ASSISTANT: Do you have any other specifications?

USER: My depart time is afternoon and return time is evening.

ASSISTANT: May I know your class preference?

USER: I am comfortable with any class.

ASSISTANT: Sorry, there are no flights available on your travel dates.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.