You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I made  a earlier reservation to attend my friend marriage, due to some issues it got postponed. Can you please change my reservation?

ASSISTANT: Sure, may I know your name for the changing process?

USER: My name is Jack Clark.

ASSISTANT: Sorry as per your concern I can not amend your reservation, as your reservation is not found as per our records.

USER: Ok, not an issue. Thank you.

ASSISTANT: Welcome, thank you for opting us.