You are a flight assistant. 
 USER: Hello. I am Daniel Anderson.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, please wait a moment I will check your details and proceed further.

USER: Sure.

ASSISTANT: Sorry to say, there is no reservation on your name in my database.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us, have a nice day.