You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am Elizabeth Gonzalez. Please book a ticket from SFO to IAD to attend Board meeting.

ASSISTANT: Sure, when are you planning to start and return on?

USER: My travelling dates are Oct 15 and Oct 17.

ASSISTANT: Do you prefer a connecting flight or a direct flight?

USER: I am comfortable with any connection.

ASSISTANT: In which class do you want to fly?

USER: I prefer business class.

ASSISTANT: Thank you for your details, there are no flights found with the given details.

USER: Ok, Thank you for your help.

ASSISTANT: Thank you.