You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: Can you please help me to book a ticket from DCA to PHX?

ASSISTANT: Sure, May I know the journey dates?

USER: I want to start on Feb 16 and return on Feb 18.

ASSISTANT: Do you have any connection limit?

USER: Yes, I need a connecting flight.

ASSISTANT: Do you have any airline preference?

USER: No.

ASSISTANT: Is there any other requirements?

USER: I would prefer a economy class.

ASSISTANT: May I know your name?

USER: Jessica Lee here.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for opting us.