You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: I am Charles Robinson. I am planning to change my reservation to another destination, so can you help me to change my reservation?

ASSISTANT: Sure Charles Robinson, I will help you with that Changing. Please hold for a moment, let me check your previous reservation status.

USER: Ok.

ASSISTANT: Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: That's ok, thank you.

ASSISTANT: You are welcome, thank you for contacting us.