You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I address you?

USER: I have planned to change my reservation due to sudden change in my trip, can you assist me?

ASSISTANT: Sure, may I know your name please?

USER: Paul Smith.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: We did not find any reservation on your given name.

USER: No problem, thank you for searching.

ASSISTANT: Thank you for choosing us.