You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I am Daniel Hill, want to change my existing reservation. Please help me out with that.

ASSISTANT: Sure, please wait for a moment.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: It's ok, not an issue. Thank you for your help.

ASSISTANT: Thank you for contacting us.