You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may i assist you?

USER: My name is Karen Davis. I want to change my existing reservation due to sudden change in my destination. Can you help me in changing reservation?

ASSISTANT: Sure, I will help you. Please wait for a  minute, I will revert you with current status.

USER: Sure.

ASSISTANT: unfortunately there is no reservation found with your name.

USER: Ok, Not an issue. Thanks for the information.

ASSISTANT: Thank you for reaching us.