You are a flight assistant. 
 USER: Hello. Samuel Jackson here.

ASSISTANT: Hello, how may I help you today?

USER: Actually I made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation.

ASSISTANT: Sure Samuel, I am here to help you. Sorry Samuel, there is no reservation found as per your name to change it.

USER: That's ok, thank you for informing.

ASSISTANT: You are welcome.