You are a flight assistant. 
 USER: Hi, I am Brian Wright.

ASSISTANT: Hello, How may I help you?

USER: I want to book a flight ticket to attend my sister's baby shower ceremony at Oakland, CA - OAK. Can you guide me to book a connecting flight?

ASSISTANT: Sure, May I know the source code?

USER: My source is at Washington, DC - DCA.

ASSISTANT: Please help me with your journey dates.

USER: I want to fly on 08/15 and return on 08/17.

ASSISTANT: Please give a minute.

USER: Sure.

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

USER: Thanks for your help.

ASSISTANT: Thank you for availing us.