You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I have to visit Washington city to attend a meeting, can you please help me to book a flight ticket from Oakland?

ASSISTANT: Ok, can you specify your airport codes?

USER: Thank you. My preferred airport codes are OAK and DCA.

ASSISTANT: Can you share your trip dates?

USER: The preferred travel dates are Nov 25 and Nov 27.

ASSISTANT: Do you need any connections?

USER: I didn't have any preferences.

ASSISTANT: May I know your name?

USER: My name is David Clark.

ASSISTANT: Flight number 1000 with price 100 in economy class is available. Is it ok?

USER: Yes, please proceed with the ticket booking.

ASSISTANT: Your ticket is booked.

USER: Thank you for your guidance in reserving the flight ticket.

ASSISTANT: Thank you for reaching us.

USER: Most welcome.