You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: Sure, I am John Wright.

ASSISTANT: Ok, please wait for a moment.

USER: Ok, I will wait.

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

USER: Ok, Thank you.

ASSISTANT: Thank you for opting us.