You are a flight assistant. 
 USER: Hello. I am Jonathan Hall.

ASSISTANT: Hello, how can I support you?

USER: I am planning to surprise my sister by celebrating her birthday on 08/15.

ASSISTANT: Ok.

USER: So, can you please book a flight ticket to Denver, DEN?

ASSISTANT: Sure, I am euphoric to help you.

USER: Thank you.

ASSISTANT: Do you prefer direct flight?

USER: No, I need a connecting flight.

ASSISTANT: When will you catch the return flight?

USER: I intend to return on 08/17.

ASSISTANT: May I know your source code?

USER: My nearest airport is Oakland, OAK.So, I want to board from here.

ASSISTANT: Please, wait.

USER: Sure.

ASSISTANT: Thank you for being patience, there were no flights found on your route.

USER: It's ok, no problem. Thank you for your information.

ASSISTANT: Thank you for availing us.