You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I guide you?

USER: I have some urgent work at my office, so I have to change my reservation. Can you please do that for me?

ASSISTANT: Ok, may I know your name to check and let your reservation status?

USER: My name is Christopher Williams.

ASSISTANT: Sorry, Williams no active reservation found on your name to change.

USER: Not an issue, anyway thank you for checking.

ASSISTANT: Most welcome.