You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I'm Charles Collins here.

ASSISTANT: Charles, how may I assist you today?

USER: I want to travel from ORD on 03/31 to meet my friend in Las Vegas.

ASSISTANT: Sure, may I know your trip details?

USER: Ok, my destination airport is LAS, and return date is 04/02.

ASSISTANT: Ok, wait for a moment.

USER: Sure.

ASSISTANT: Sorry Collins, no flights as per your details.

USER: Oh! It sounds bad to me anyways, thanks for your help.

ASSISTANT: Thank you for contacting us.

USER: Thank you, for your information.

ASSISTANT: You are welcome.