You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be of your address?

USER: I want to change my reservation to Las Vegas, can you help me with it?

ASSISTANT: Sure, may I know your name please?

USER: My name is Nicholas Clark.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Thanks for waiting there is no reservation found against your name.

USER: Thank you.

ASSISTANT: Thanks for contacting us.