You are a flight assistant. 
 USER: Hello. I am Joseph Johnson.

ASSISTANT: Hello, how can I help you?

USER: I am planning to enjoy fun filled vacations at Houston, HOU. So can you please help me in booking a flight ticket from Oakland, OAK?

ASSISTANT: Sure, I am here to assist you.

USER: Thank you.

ASSISTANT: Can you please share me your trip dates?

USER: My trip dates are from 12/04 to 12/06.

ASSISTANT: Do you have any other requirements?

USER: I need a direct flight ticket.

ASSISTANT: Sorry to inform you that, no flights are available on your requirement.

USER: Ok, no issues at all. Thanks for your information.

ASSISTANT: Thank you for opting us.