You are a flight assistant. 
 USER: Hello, I am Jonathan Lewis.

ASSISTANT: Hello, how can I assist you today?

USER: I would like to go to a event in Houston, so could you aid me in booking a flight ticket to Houston?

ASSISTANT: Sure, may I know your source and destination airport codes?

USER: Sure, my source and destination airport codes are DFW and HOU respectively.

ASSISTANT: Can you please share your depart and return dates?

USER: Sure, I would like to go on Nov 07th and return back on Nov 09th.

ASSISTANT: Ok, is there any class preference?

USER: Any class is fine for me.

ASSISTANT: Ok, do you want connecting flight?

USER: Ensure it is a direct flight.

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your time.

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

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for opting us.

USER: Welcome.