You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Deborah Thompson here.

ASSISTANT: How can I serve you today?

USER: I want to visit historical places in Houston, so please book my ticket from Oakland.

ASSISTANT: Could you please provide me your trip dates?

USER: My trip dates are 12/04 and 12/06.

ASSISTANT: May I know your airport codes please?

USER: My origin and destination airport codes are OAK and IAH.

ASSISTANT: Please wait for a minute.

USER: Ok.

ASSISTANT: Sorry Thompson, no flight is available for you as per your details.

USER: It's ok, thank you.

ASSISTANT: Thank you for contacting us.