You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you.

USER: I want to change my existing reservation . Can you help me for that one?

ASSISTANT: Sure, may I know your name please?

USER: Sure, Nicole Hall here.

ASSISTANT: I am sorry no reservation found on your name.

USER: No issues, thank you for the information.

ASSISTANT: Thank you for choosing us.