You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, May I know the travelling dates?

USER: I will start on May, 5 and return on May, 7.

ASSISTANT: Do you have any connection limit?

USER: I would prefer single connection.

ASSISTANT: Is there any other requirements?

USER: No, thank you.

ASSISTANT: May I know your name?

USER: Brandon Thomas here.

ASSISTANT: Please wait a minute.

USER: Sure.

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

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for reaching us.