You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, may I know your airport codes?

USER: Sure, my boarding and landing airport codes are DFW and SEA.

ASSISTANT: May I know your trip dates?

USER: I would like to depart on 09/19 and my return date will be on 09/21.

ASSISTANT: Is there any class preference?

USER: I prefer to fly in an economy class.

ASSISTANT: Do you have any other requirements?

USER: No more specifications.

ASSISTANT: May I know your good name?

USER: I am Stephen Hill.

ASSISTANT: I regret to inform you that there were no flights found as per your requirement.

USER: That's ok, no issues. Thank you for your information.

ASSISTANT: Thank you for reaching our service.