You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Kathleen Hernandez here.

ASSISTANT: Kathleen Hernandez. How may I help you?

USER: Please help me out in booking the ticket from OAK to DCA.

ASSISTANT: Sure, can you provide me with the travel dates.

USER: My trip dates will be July 10 to July 12.

ASSISTANT: Do you have any preferences?

USER: I want my return journey in the afternoon.

ASSISTANT: Give me a moment.

USER: Ok.

ASSISTANT: Sorry there are no flights on the days you have preferred.

USER: That's ok, thank you.

ASSISTANT: Thank you for approaching us.