You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Mark Miller. I am planning to celebrate my cousin birthday at Francisco, CA - SFO. Can you help me with book a ticket fare of 200?

ASSISTANT: Sure, May I know your source airport code?

USER: My source airport code is Atlanta, GA - ATL.

ASSISTANT: Let me know your travelling dates please.

USER: My travelling dates are 03/17 to 03/19.

ASSISTANT: Do you need a halt within your journey?

USER: Yes, I need a halt in between my journey.

ASSISTANT: Ok, give me a minute.

USER: Sure.

ASSISTANT: There is a Frontier airline with flight number 1012 and price of 100.

USER: OK, please proceed to book.

ASSISTANT: Your booking is done.

USER: Thanks for you kind assistance.

ASSISTANT: Thank you for opting us.