You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you at this moment?

USER: I want to book a direct flight to Los Angeles, LAX to meet my sister. Can you please help me for booking?

ASSISTANT: Sure, may I know your boarding airport code?

USER: Sure, my boarding airport code is DFW.

ASSISTANT: When would you like to make your journey?

USER: My travelling dates are July 16 and July 18.

ASSISTANT: May I know your name please?

USER: Sure, I am Sarah Phillips.

ASSISTANT: Sorry, there are no flights are available matching your credentials.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for opting us.