You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you  at this moment?

USER: I would like to book a flight ticket to Dallas to take a part in scuba driving, could you please help me to book a flight ticket with single connection?

ASSISTANT: Sure, can you please let me know your journey dates?

USER: Sure, I am planning to start my journey on Feb 23rd and I'll return within two days that is on Feb 25th.

ASSISTANT: Kindly assign your source and destination airport codes?

USER: I want to start my journey from DCA and my landing airport code is DFW.

ASSISTANT: Is there any more specification do you need?

USER: I prefer to fly in economy class.

ASSISTANT: May I know your name please?

USER: I am Nicole Smith.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that, we did not find any flights matching your journey dates.

USER: That's ok, I'll choose any alternative to reach my destination. Thank you for your information.

ASSISTANT: Thank you for approaching us.