You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Richard Garcia. Suddenly I got a call from my manager to attend a meeting, so I need to change existing reservation. Can you please help me?

ASSISTANT: Sure, I am ravish to help you.

USER: Ok, thank you.

ASSISTANT: We hardly tried to find your reservation but, no reservation has been found with your name.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for your positive response.