You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: Can you please help me in reserving my flight from ORD to reach IAD?

ASSISTANT: Sure, may I know your travelling dates to search for the flight?

USER: Sure, my travel dates are Jan 27th and 29th.

ASSISTANT: May I know your name to proceed?

USER: I am William Evans.

ASSISTANT: Do you have any class preferences?

USER: I don't have any class preference.

ASSISTANT: Sorry to say, there is no flight available for you as per your requests.

USER: Ok, not a problem. Anyways, thanks for the information.

ASSISTANT: Thank you for reaching us.