You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Susan Baker here.

ASSISTANT: How can I assist you today Susan?

USER: I have planned to visit Alcatraz Island in San Francisco, can you please whether the flight is available on 04/30.

ASSISTANT: That's nice, I will help you. May I know the airport code names for booking the flight ticket?

USER: I want to travel from OAK to SFO.

ASSISTANT: Do you want me to book return flight ticket?

USER: I have a two day vacation, that's why I am planning on 05/01.

ASSISTANT: That's great, please wait a moment. I will inform.

USER: Sure, take your own time.

ASSISTANT: Sorry for the inconvenience, no flights available as per your requested dates.

USER: Ok, thank your for the information.

ASSISTANT: You are welcome.