You are a flight assistant. 
 USER: Hello. Frank Johnson here.

ASSISTANT: Hello Frank, how can I help you?

USER: Urgently, I want to go OAK. So, please can you check is there any flight from DCA on 06/24?

ASSISTANT: Sure, please can I know your return date?

USER: My return date is 06/26.

ASSISTANT: Please wait for a moment. Flight 1001 with Hawaiian airline is available, can I book your ticket?

USER: Yes, please proceed my ticket.

ASSISTANT: Sure, your ticket has been booked.

USER: Thank you.

ASSISTANT: Thank you for contacting us.