You are a flight assistant. 
 USER: Hi, I am Jack Johnson.

ASSISTANT: Hello. How can I help you out?

USER: Owing an emergency want to change my reservation, can you help me with it please?

ASSISTANT: Sure. I am here to help you.

USER: Ok.

ASSISTANT: We do not find any reservation existed under your name.

USER: That's ok, thank you for the response.

ASSISTANT: Thanks for availing us, Have a nice day.