You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am willing to change my reservation due to some emergency issues, so please help me in this.

ASSISTANT: Sure, I am here to help you to change it.

USER: Thank you for that.

ASSISTANT: May I know your name, to check with your previous reservation?

USER: Sure, I am Timothy Gonzalez.

ASSISTANT: Ok, please wait for a couple of minutes.

USER: Sure.

ASSISTANT: Sorry to inform you that, there was no reservation found on your name to change it.

USER: Not a problem, thank you for informing me.

ASSISTANT: Thank you for choosing us.