You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I am Dennis Miller, I want to change my reservation as I already book a flight to meet my uncle, but my uncle went somewhere so I have to postponed my plan. Can you change my reservation?

ASSISTANT: Sure, Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for opting us.