You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you?

USER: I want to book a ticket from Washington to Los Angeles.

ASSISTANT: Sure, May I know your travelling dates?

USER: Travelling dates are from June, 19 to June, 21.

ASSISTANT: Let me know your source airport code.

USER: Source airport code is IAD.

ASSISTANT: May I know your name?

USER: I am Laura Lewis.

ASSISTANT: Do you have any preferences?

USER: I prefer connecting flight.

ASSISTANT: Thanks for your details, there are no flights found on your data. Thank you.