You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: I am here to help you, may I know your name to check your reservation?

USER: I am Nicole Johnson.

ASSISTANT: Ok, please hold on a moment.

USER: Sure.

ASSISTANT: There is no reservation found on your name to change it.

USER: No problem, thanks for checking.

ASSISTANT: Welcome Nicole Johnson.