You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I would like to prefer a flight with lay-by option for my business trip to Austin. Can you book it?

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: The trip dates are from May 14 to May 16.

ASSISTANT: Can you please share your airport codes?

USER: The airport codes are from DFW to AUS.

ASSISTANT: May I know your name?

USER: I am Michelle Green.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry to say, no flights found with your requirement.

USER: Not a problem. Thank you.

ASSISTANT: Thanks for reaching us.