You are a flight assistant. 
 USER: Hi, I am William Robinson.

ASSISTANT: Hello, how can I aid you?

USER: I want to attend a family function at Las Vegas, NV-LAS, can you please book me a ticket?

ASSISTANT: Sure, can you help me with your journey dates?

USER: My journey dates are from 01/18 to 01/20.

ASSISTANT: May I know your origin point?

USER: My source airport code is Atlanta, GA-ATL.

ASSISTANT: May I know your price limit?

USER: My budget limit is 200.

ASSISTANT: Sorry, no flights found on your given fare.

USER: Ok, thank you for your information.

ASSISTANT: Thank you for reaching us.