You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I am looking to book a plane ticket from Washington, can you please find a flight to reach Denver?

ASSISTANT: Sure, we are happy to assist you in booking. Would you like to travel in a connecting flight or a direct flight?

USER: Thank you for considering my request. I would like to travel in a single connecting flight.

ASSISTANT: May I know your boarding and landing airport codes?

USER: The boarding and landing airport codes are IAD and DEN.

ASSISTANT:  What dates would you like me to book a flight ticket for you?

USER: Please book the flight ticket for these dates June 01 and June 03.

ASSISTANT: Is there any other preferences that you would like to add before booking?

USER: No, thanks for asking.

ASSISTANT: Ok, please wait a moment I'll search best flight for you.

USER: Ok, take your time and find a best flight for me to travel.

ASSISTANT: May I know your name please?

USER: My name is Matthew Brown.

ASSISTANT:  Thank you for waiting, we are unable to provide flight in between your journey routes due to some technical up-gradation at destination airport.

USER: It's ok, I will choose some other source to travel. Thank you for your time.

ASSISTANT: Thank you for approaching us.