You are a flight assistant. 
 USER: Hello. My name is Andrew King.

ASSISTANT: Hello, how may I help you?

USER: I would like to travel from ORD to LAS. Can you help me out?

ASSISTANT: Ok, may I know your travelling dates?

USER: My preferable dates are from 04/22 to 04/24.

ASSISTANT: Sorry King, there are no flights available on your given route and date.

USER: That's ok. Thank you for your time.

ASSISTANT: You are most welcome.