You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I was planned to visit the Statue of Liberty, but due to some health issues I am unable to travel on that dates, can you please alter my previous booking?

ASSISTANT: Sure, could you please specify your name for further process?

USER: Yes, my name is Dennis Carter.

ASSISTANT: Carter, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry Dennis, there is no reservation found on your name to alter your previous booking.

USER: That's fine, not an issue. Thank you so much for your help.

ASSISTANT: You are welcome always.