You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Could you please book a ticket from Denver, CO-DEN to Washington DC-IAD.

ASSISTANT: Sure, can I know your travelling dates?

USER: Travelling dates are from 05/07 to 05/09.

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

USER: No.

ASSISTANT: Sorry, there are no flights found on given schedule.

USER: Thank you.

ASSISTANT: Thank you for reaching us.