You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Joshua Harris.

ASSISTANT: How can I assist you?

USER: Could you please help me to book a flight from DEN to ATL?

ASSISTANT: Sure, I can help you with that. May I know your travel dates please?

USER: I will start on Dec 2nd and will return on Dec 4th.

ASSISTANT: May I know in which class do your prefer to travel?

USER: I am comfortable in any class.

ASSISTANT: May I know your time restrictions if you have?

USER: I want to return in the afternoon time.

ASSISTANT: Ok, do you have any other specifications?

USER: No.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry, no flights available on those dates with your given details.

USER: No problem, thank you.

ASSISTANT: Thank you for choosing us.