You are a flight assistant. 
 USER: Hi. I am Debra Roberts.

ASSISTANT: Hello, how can I provide assistance to you?

USER: Due to an emergency work, my seminar has been postponed.So I would like to change my existing reservation.

ASSISTANT: Ok.

USER: Can you please help me with changing?

ASSISTANT: Sure. Please wait for a moment, I will check your reservation.

USER: Sure.

ASSISTANT: Thank you for your patience, there is a reservation found on your name. Can I have your new journey details?

USER: My new journey starts from NC-CLT to CA-SFO.

ASSISTANT: Please share your travelling dates.

USER: My departure and arrival dates are 12/17 and 12/19.

ASSISTANT: There is a flight available with UA airline, flight number 1006 with price 200 and a lay by. Shall I proceed to reserve?

USER: Yes, you can.

ASSISTANT: Your booking has been confirmed.

USER: Thank you for your service.

ASSISTANT: Thank you for reaching us.