You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I be of your address?

USER: I am Dorothy Clark. I want to change my existing reservation due to sudden demise of my grandfather. Can you help me to change?

ASSISTANT: Sure, give me a minute.

USER: Sure.

ASSISTANT: Tnaks for waiting, we are happy to inform you that there is a reservation on this name. May I know your updated travelling dates?

USER: Thank you. Ok, travelling dates are on 02/19 and 02/21.

ASSISTANT: Please let me know your source and destination points.

USER: Airport codes are from New York, JFK to San Francisco, SFO.

ASSISTANT: Is there any connection preference?

USER: Yes, I need single halt.

ASSISTANT: We found an UA airline matching your details with one connection and the flight number-1016.

USER: Proceed for booking.

ASSISTANT: Your booking has been processed successfully.

USER: Thank you.

ASSISTANT: You're welcome. Happy journey.