You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am Virginia Williams. Can you please reserve me a flight ticket from Seattle, WA - SEA to Denver, CO - DEN?

ASSISTANT: Sure, I am here to help you in booking. May I know your travel dates please?

USER: My trip dates are Dec 4 - Dec 6.

ASSISTANT: Do you need any halt in between your journey?

USER: I am ok with direct or connecting flight.

ASSISTANT: Which class do you prefer for your journey?

USER: I prefer to go by an economy class.

ASSISTANT: Ok, please be on hold.

USER: Please make sure that my depart time should be in the afternoon. Sure, I will wait.

ASSISTANT: Sorry to inform you that, there are no flights for the departure time that you have requested for.

USER: Not a problem, thank you for your service.

ASSISTANT: Thank you for approaching us.