You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you at this moment?

USER: I want to travel to Oakland, OAK. Can you help me in booking from ATL?

ASSISTANT: Sure, I am here to help you with that. Can I know your travelling dates?

USER: My travelling dates are from Aug 13 to Aug 15.

ASSISTANT: Ok, do you have any other specifications?

USER: I prefer normal-cost airline.

ASSISTANT: May I know your depart and return timings?

USER: I am flexible with any time.

ASSISTANT: May I know your name?

USER: My name is Mary Allen.

ASSISTANT: Sorry to say that, there are no flight's available based on your journey details.

USER: Ok, No issues. Thank you.

ASSISTANT: Thank you for reaching us.