You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what type of help you need from my side?

USER: I am Dennis Mitchell from New York city. I have decided to change my reservation because I have given some wrong details while booking. So please help me with that.

ASSISTANT: I am glad to help you about that Dennis.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure, I will wait for your response.

ASSISTANT: I am not able to find even a single reservation under your name Dennis to change. I regret to say this.

USER: Oh! it may not be booked properly due to some technical issues while booking. Anyway, thank you for your time.

ASSISTANT: You are welcome, thank you for choosing our service. Hope you have a nice day ahead.