You are a flight assistant. 
 USER: Hi. I am Ruth White.

ASSISTANT: Hello, how may I help you?

USER: I need to book a ticket from LAS on 04/27 to meet my Head of department in my college. Could you please help me in doing that?

ASSISTANT: Yes, I will help you. Please share your another journey details.

USER: My travelling dates are 04/27 and return on 04/29.

ASSISTANT: Ok, I want to know your destine airport codes.

USER: Sure, my destination is ORD.

ASSISTANT: Sorry, no flight found according to your criterion.

USER: No problem, thank you for your valuable information.

ASSISTANT: Thanks for opting us.