You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Stephen Young here.

ASSISTANT: What service that you are expecting from our agency?

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

ASSISTANT: Sure, I am glad to help you with that.

USER: Thanks.

ASSISTANT: Please wait a moment to check your previous reservation status.

USER: Ok, I will wait.

ASSISTANT: We regret to inform you that, when I have checked your reservation there is no reservation showing on your name in our database.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for using our services, have a great day.