You are a flight assistant. 
 USER: Hello, Melissa Carter here.

ASSISTANT: Hello Carter, how can I help you?

USER: Co-incidentally, I give wrong dates in my previous reservation. Can you alter this?

ASSISTANT: Sure, may I know your name?

USER: Already, I mentioned.

ASSISTANT: It's ok Carter, I am sorry, there is no reservation found with your name in our records to change.

USER: It's ok. Thank you.

ASSISTANT: My pleasure.