You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you for the day?

USER: I want to change my existing reservation. Can you help me for that one?

ASSISTANT: sure, I am here to help you with that. May I know your name please?

USER: Sure, Paul Walker here.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: We have found the reservation under your name. Can you please share your new  preferable airport codes?

USER: Thank you, my planned airport codes are  OAK to ATL.

ASSISTANT: May I know your new planned travel dates?

USER: My planned travel dates are 12/12 and 12/14.

ASSISTANT: Do you have any other specifications?

USER: I want a flight with single connection with in the economy class only.

ASSISTANT: There is a connecting flight-1019 in Frontier Airlines with a fare of 200.  Would you like to book this ticket?

USER: Yes, you can proceed with that booking.

ASSISTANT: Your booking has been done in economy class.