You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How can I help you today?

USER: I need to buy a plane ticket. Please help me in that.

ASSISTANT: Sure, can I have your name please?

USER: I am David Smith.

ASSISTANT: Let me know your airport codes?

USER: My source airport code is SEA and destination airport code is PHX.

ASSISTANT: Please share me your trip dates?

USER: My journey dates are from Jan, 23 to Jan, 25.

ASSISTANT: Do you have any connection limit?

USER: Yes, I prefer a single connecting flight.

ASSISTANT: Any other preferences?

USER: I need to travel in business class.

ASSISTANT: Sorry, no flights found with your given details.

USER: Ok, thanks for your information.

ASSISTANT: Thank you for reaching us.