You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Christopher Williams. Can you please book a flight ticket from MCO to DEN?

ASSISTANT: Sure, may I know your travelling dates?

USER: Sure, I need to travel on dates of Apr 29 and May 01.

ASSISTANT: Do you have any class preference?

USER: No, I am ok with any class.

ASSISTANT: May I know your other requirements?

USER: Sure, I would like to depart in the morning time.

ASSISTANT: Sorry, there are no flights available on your travelling dates.

USER: Oh! it is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you.

USER: Most welcome.