You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be your helping hand?

USER: I planned to visit Oakland to visit Angle island with my family, can you help me to book a flight on 07/11?

ASSISTANT: Sure. Can I have your airport codes please?

USER: Sorry I like to travel on 08/11. My source airport is Detroit, MI-DTW and destination is CA-OAK.

ASSISTANT: May I know when you are planning to return?

USER: My returning date is 08/13.

ASSISTANT: Do you have any specifications?

USER: I want a flight with one halt. Price limit is 500.

ASSISTANT: Please hold on for a moment.

USER: Sure.

ASSISTANT: Unfortunately there are no flights available with your specified dates.

USER: Ok, thanks for your service.

ASSISTANT: May I know your good name please?

USER: I am Michelle Thomas.

ASSISTANT: Thank you for opting us.