You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My friend birthday party place has been changed to New York, can you please change my existing reservation?

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: Please mention your name to check your previous reservation.

USER: Sure, I am Donald Miller.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Ok, Thank you.

ASSISTANT: Welcome, have a nice day.