You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Sarah Hall.

ASSISTANT: How can I help you today?

USER: I am looking to book a flight ticket from DFW to ORD, can you help me for booking?

ASSISTANT: Sure, can you please share your trip dates?

USER: My travelling dates are from 10/17 till 10/19.

ASSISTANT: Sorry, no flights are available on your route.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome.