You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I provide service to you?

USER: Can you help me to book a flight ticket from OAK to IAD?

ASSISTANT: Sure, on which dates would you like me to book a flight ticket for you?

USER: My travelling dates are 21 and 23 of Dec.

ASSISTANT: Do you need a stopover in between your journey?

USER: I need a connecting flight.

ASSISTANT: Please let me know if you have any other preferences.

USER: No.

ASSISTANT: May I know your name for documentation purpose?

USER: I am Emily Gonzalez.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: Sorry, there were no flights found on your preferable travel dates.

USER: It's ok, not a problem, thank you.

ASSISTANT: Thank you for approaching us.