You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, can I know your name?

USER: My name is William Mitchell.

ASSISTANT: Ok, please wait for a while.

USER: Ok, I will wait.

ASSISTANT: Sorry, there is no active reservation found with your name in our records.

USER: Anyway, thanks for the information.

ASSISTANT: Most welcome.