You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am John Lee. I am planning to book a ticket with 0 connection, can you please help me out to book a flight ticket for me?

ASSISTANT: Yes, I can help you with that.

USER: Thank you.

ASSISTANT: Can you share me your nearest source airport code for this journey?

USER: My nearest  source airport code is DFW.

ASSISTANT: Ok, could you please tell me your departure date?

USER: I would like to start my journey on 10/18.

ASSISTANT: Can I know your return date for this journey?

USER: I am planning to return on 10/20.

ASSISTANT: Ok, could you tell me your destination airport code?

USER: My destination code is LAX.

ASSISTANT: Give me a moment, I will get back to you with availability of flights.

USER: Sure, I will wait but try to find a best airline for me.

ASSISTANT: Sorry to inform you that there are no flight services found providing service on your requested route.

USER: That's not a issue. Thank you for your service.

ASSISTANT: Thank you for reaching our agency.