You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Richard Robinson, I want to change my existing reservation. Can you help me with that?

ASSISTANT: Sure, we are here to help you. Please wait a moment I will check and revert to you.

USER: OK.

ASSISTANT: Sorry to say, no reservation found on your given name.

USER: Ok, no issues. Thanks for making your safe service so kind.

ASSISTANT: Thank you for opting us for your change reservation. Have a nice day.