You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I will help you with that.

USER: Thanks.

ASSISTANT: Let me know your name to check your reservation?

USER: My name is Gregory Jackson.

ASSISTANT: Ok, please wait a moment.

USER: Ok, I will wait.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for choosing us.