You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, may I know your name?

USER: Jeffrey Thomas.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there no reserve reservation on your name.

USER: No issues, thank you.

ASSISTANT: Thank you.