You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you today?

USER: I am planning to attend a Seminar at Denver,can you help me with booking?

ASSISTANT: Sure, I will help you with booking. Please share me source and destination airport codes?

USER: My airport codes are  IAD to DEN.

ASSISTANT: Please mention when you planned to travel?

USER: My travel dates are June 24 and June 26.

ASSISTANT: Do you want a connecting flight for your journey?

USER: Yes, I need a connecting flight.

ASSISTANT: Is there any other preferences related to booking?

USER: No.

ASSISTANT: May I know your good name?

USER: I am Helen Green.

ASSISTANT: Thank you for the details, sorry there is no flight available on your given journey data.

USER: Ok, no problem. Thank you for your response.

ASSISTANT: Thank you visiting us, we hope see you again.