You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How may I help you?

USER: Frank Mitchell here. I want to travel in a flight with price defence of 200, can you please help me in booking a ticket?

ASSISTANT: Sure. Please help me with your travelling codes.

USER: The travelling dates are from 02/08 to 02/10.

ASSISTANT: Please specify travel codes.

USER: Source airport code is SFO and destination airport code is LGA.

ASSISTANT: No flights found with your requirement.

USER: That's ok, I will try alternate way to complete my trip.

ASSISTANT: Thanks.

USER: Thank you for your help.