You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I want to travel from BOS to DEN, can you help me in doing a reservation?

ASSISTANT: Sure, may I know the travelling dates?

USER: Apr, 16 and Apr, 18 are my trip dates.

ASSISTANT: Do you have any connection limit?

USER: I need direct flight.

ASSISTANT: Are there any other requirements?

USER: I need to return at evening time with business class.

ASSISTANT: May I know your name?

USER: Virginia Walker here.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, no flights found with your chosen dates.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for opting us.