You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Is this ticket booking agency?

ASSISTANT: Yes, this is ticket booking agency.

USER: I am Ronald Clark. I think I'm in right place to book a flight ticket.

ASSISTANT: Yes.

USER: I want to fly on 02/01.

ASSISTANT: Ok, can I know your travelling airport codes?

USER: I am planning to travel to OAK for visiting to zoo.

ASSISTANT: Could you tell me your return date and source airport code?

USER: Sure. I will return on 02/03, from MSP.

ASSISTANT: Ok. Give me a moment.

USER: Ok.

ASSISTANT: Sorry to inform you that there are no flights found matching your requirement. Thank you for reaching us.

USER: That's ok. Thank you.