You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I assist you?

USER: I am Stephanie Edwards.

ASSISTANT:      Ok.

USER: I am planning to visit NASA space center in Houston TX - HOU, can you please help me to book a flight ticket from OAK?

ASSISTANT: Yes, I am here to help you. Can I know on which dates you want to travel?

USER: Sure, the trip dates are 07/20 to 07/22.

ASSISTANT: Ok, how much you can pay for this ticket?

USER: I can spend upto 500.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, we are sorry to inform we didn't find any flights with your details.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us, have a nice day.