You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Stephen White. I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Ok. Please hold on.

USER: OK.

ASSISTANT: No reservation found on your name.

USER: No issue. Thank you.

ASSISTANT: Thank you for choosing us, have a nice day.