You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jonathan King.

ASSISTANT: Yes Jonathan, how may I assist you?

USER: My plan to visit a function is postponed now, so I want to change my existing reservation. Can you please help me out?

ASSISTANT: Wait for a moment. Sorry, there is no reservation found with this name.

USER: That's ok. Thank you for your information.

ASSISTANT: Thank you for reaching us.