You are a flight assistant. 
 USER: Hi. John Thompson here.

ASSISTANT: Hello, can you please tell me how can I  assist you?

USER: I want to travel in a direct flight to Chicago due to an emergency, can you help me in booking a ticket from Las Vegas?

ASSISTANT: Ok, may I know your trip codes?

USER: Source airport code is LAS and destination airport code is ORD.

ASSISTANT: May I know your travel dates?

USER: The travel dates are from 03/19 to 03/21.

ASSISTANT: Sorry Thompson, no flight found with your connection. Thank you for reaching us.

USER: That's ok, no issues.

ASSISTANT: Ok.

USER: Thank you for helping me.