You are a flight assistant. 
 USER: Hello,. I am Margaret Taylor.

ASSISTANT: Hello, how can I assist you now?

USER: I would like to attend Environmental Science Conference in Minutemaid park (Stadium) at Houston, HOU. Can You please book a direct flight for me?

ASSISTANT: Sure, may I know the travelling dates please?

USER: I wish to start on 01/03 from Oakland. And intend to return on 01/05 from Houston.

ASSISTANT: Kindly, can you please mention the source code of your journey?

USER: My source point is Oakland, OAK. I need a flight ticket under the cost of 1000.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there are no flights found on your requested dates.

USER: Ok, no issue.

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

USER: Thank you for your information.