You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: My name is Catherine Robinson, I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, we couldn't find a reservation on your name.

USER: Not an issue, thank you.

ASSISTANT: Thank you for choosing us.