You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation due to some problems, can you please help me?

ASSISTANT: Sure, I am gleeful to help you out. Please provide me your name.

USER: Sure, my name is Jeffrey Roberts.

ASSISTANT: Please wait a moment.

USER: Sure, take your time.

ASSISTANT: Sorry Roberts, there is no active reservation on your name in our database.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Thank you for reaching us.