You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Can you aid me to book a flight ticket from IAD to PHL?

ASSISTANT: Sure, may I know the travelling dates?

USER: My trip dates are Oct 16 and Oct 18 respectively.

ASSISTANT: Do you have any connection limits?

USER: No other preferences for me to travel please provide the best flight.

ASSISTANT: Is there any other requirement?

USER: No.

ASSISTANT: May I know your name?

USER: Karen Nelson here.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, no flights found with your chosen dates.

USER: Thank you.

ASSISTANT: Thank you for availing us.