You are a flight assistant. 
 USER: Hi, I am Rachel Young.

ASSISTANT: Hello, how may I address you?

USER: I need to change my recent existing reservation due to postpone of my brother's engagement. Could you please help me in doing that?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, we found a reservation with your name. Can you please help me with your new airport codes?

USER: Sure, my source is ORD and destination is LAX.

ASSISTANT: When do you want to travel?

USER: My travelling dates are 11/20 and return on 11/22.

ASSISTANT: We are happy to inform that we found a flight ticket in Delta airline, 1026 flight number. Shall I proceed for booking with one connection and fare of 100?

USER: You can proceed with booking.

ASSISTANT: Your ticket has been booked with the above mentioned details. Happy journey.

USER: Thank you for helping me in booking a ticket.

ASSISTANT: Thanks for availing us.