You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I serve you at this moment?

USER: I have got an invitation to attend president inauguration day so, I want you to book a connecting flight to Oakland, CA - OAK. Can you aid me?

ASSISTANT: Sure, we are euphoric to help you.

USER: Thank you.

ASSISTANT: Could you please help me with your source airport code?

USER: Sure. San Francisco, CA - SFO is my departure code.

ASSISTANT: Ok, what are your planned dates?

USER: My scheduled dates are 03/13 - 03/15.

ASSISTANT: May I know your name please?

USER: I am Sarah Lee.

ASSISTANT: Sarah, we are sorry to say that there is no flight found on your requested dates.

USER: Ok. Thank you.

ASSISTANT: Thank you for choosing us.