You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am planning to visit Denver, can you please book me a ticket from MSP to DEN?

ASSISTANT: Sure, please share me your trip dates.

USER: I would like to depart on Jan 12 and would like to return on Jan 14.

ASSISTANT: Is there any class preferences for you?

USER: I prefer business class.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I prefer direct flight for this trip.

ASSISTANT: For booking, we need your good name. Please provide it.

USER: My name is Mary Allen.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: Ok, not an issue. Thank you for providing information.

ASSISTANT: Thank you for communicating with us.