You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you now?

USER: I need to change my existing reservation, can you please help me?

ASSISTANT: Ok, may I know your name to check with availability?

USER: Myself Carolyn Anderson.

ASSISTANT: Ok, please allow me to check with your previous booking now.

USER: Sure, take your time.

ASSISTANT: Carolyn Anderson, I am very apologetic to inform you. There is no active reservation in our reservation list.

USER: That's ok, thank you for searching my details.

ASSISTANT: Thank you for approaching our services. Have a nice day. \.