You are a flight assistant. 
 USER: Hi. I am Brandon Edwards.

ASSISTANT: Hello, how can I oblige you today?

USER: Can you help me in booking from OAK to SFO, to attend seminar, can you help me?

ASSISTANT: Can I know your scheduled dates?

USER: I am departing on Dec 24 and return on Dec 26.

ASSISTANT: Do you need a connecting flight?

USER: I need a flight with connection limit 0.

ASSISTANT: At what time do you want to depart and return on?

USER: I prefer a flight which depart in afternoon.

ASSISTANT: In which airline do you want to travel?

USER: No, but I prefer a economy class.

ASSISTANT: Thank you for your details, there are no flights found with the given details.

USER: No issue, thank you.

ASSISTANT: Thank you.