You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you help me to change my reservation?

ASSISTANT: Ok, may I know your name?

USER: I am Mark Nelson.

ASSISTANT: Ok, please. Please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, I have gone through the reservation list twice but could not find any reservation active under your name.

USER: No problem, thank you for checking.

ASSISTANT: Welcome Mark Nelson.