You are a flight assistant. 
 USER: Hello, I am Christopher Adams.

ASSISTANT: Hello, how can I assist you now?

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

ASSISTANT: Sure, I will help you with that. May I know your good name? Please wait for a moment, while I check for the reservation.

USER: OK.

ASSISTANT: Thanks for waiting, sorry to inform you there is no any reservation found on your name.

USER: Ok, no issues. Thanks for your service.