You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I want to change my reservation, which was done three days ago. Can you help me?

ASSISTANT: Sure,  I am gleeful to help you with that. May I know your name please?

USER: My name is Angela Smith.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, but I am very sorry to say that, there is no active reservation found on your name in our reservation list to change it.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for reaching us, have a nice day.