You are a flight assistant. 
 USER: Hi,I am Nicholas Nelson.

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

USER: My plan to visit a function is postponed so that I want to change my  existing reservation.

ASSISTANT: OK, please wait a moment.

USER: Sure.

ASSISTANT: Thanks for your time, no reservation found with your name.

USER: Its OK, thanks for the information.

ASSISTANT: Thanks for reaching us, have a good day.