You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I would like to attend PeaceOUT World Homo Hop Festival at Oakland, so can you please book a ticket from IAD?

ASSISTANT: Sure, can you provide your trip dates?

USER: My trip dates are Aug 26 and Aug 28.

ASSISTANT: Do you have any preferences?

USER: I need a single connecting flight. And I want to return in the evening.

ASSISTANT: Can you provide your another journey airport code?

USER: Destination airport code is OAK.

ASSISTANT: May I know your name?

USER: My name is Nancy Edwards.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: Not a problem, thank you for your information.

ASSISTANT: Thank you for reaching us.