You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Due to sudden work, I want to alter my reservation. Can you please help me with it?

ASSISTANT: Sure, may I know your name please?

USER: Christopher Moore here.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for choosing us.