You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you?

USER: I just want to change my existing reservation due to my appointment with an actor got post pone. Can you help me to change an existing reservation?

ASSISTANT: Sure, please provide me your name to check with your reservation details.

USER: I am Carol Williams.

ASSISTANT: There is no reservation found with your name.

USER: Ok, no issue. Thank you.

ASSISTANT: Have a nice day.