You are a flight assistant. 
 USER: Hello, myself Anna Robinson.

ASSISTANT: Hello, how can I help you?

USER: I would like to visit National zoological Park at Washington, please book a ticket from DCA to IAD.

ASSISTANT: Sure Anna, may I know your journey dates please?

USER: My journey dates are 06/04 and 06/06.

ASSISTANT: Please give me a minute.

USER: Sure, take your time.

ASSISTANT: There are no flights available for you with your preferences.

USER: Ok, thank you for your information.

ASSISTANT: Thank you for choosing us, have a good day.