You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: Can you please book a ticket from IAD to BOS to go for Holiday trip?

ASSISTANT: Sure, may I know your planned trip dates?

USER: My travelling dates are Aug 20 and Aug 22.

ASSISTANT: Do you have any connection limit?

USER: I want single connected flight.

ASSISTANT: Is there any airline preference?

USER: No.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: Please forward your name.

USER: Sure, I am David Adams.

ASSISTANT: There are no flights found on your specified trip dates.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for availing us.