You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Steven Collins. I want to book a ticket from DEN to LAS, can you please help me?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are on Oct 29 and Oct 31.

ASSISTANT: At what time do you like to travel?

USER: I want to depart and return at afternoon.

ASSISTANT: Sorry, there is no flight on your details.

USER: Ok, thank you for informing me.

ASSISTANT: Thank you.