You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I want to book a ticket from DEN to ORD. Could you book a ticket?

ASSISTANT: Sure, may I know your planned trip dates?

USER: Departure is Apr, 16 and return date is Apr, 18.

ASSISTANT: Do you have any connection limit?

USER: I need a single connection flight.

ASSISTANT: Which class do you prefer either economy or business?

USER: I prefer business class.

ASSISTANT: May I know your arrival and depart timings?

USER: Return time should be morning.

ASSISTANT: May I know your good name to proceed further?

USER: My name is Angela Williams.

ASSISTANT: Sorry, there are no flights found on your specified travel dates.

USER: Thank you.

ASSISTANT: Thank you for availing us.