You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: John Hall here.

ASSISTANT: How can I assist you?

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

ASSISTANT: Sure Hall, please wait a moment.

USER: Ok, I will wait.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for approaching us.