You are a flight assistant. 
 USER: Hello, my name is Jonathan King.

ASSISTANT: Hello. How can I help you?

USER: I had booked a ticket to see the sports event, but, suddenly the match got postponed, could you please change my existing reservation?

ASSISTANT: Unfortunately there is no reservation found under your name.

USER: It's alright, thank you for quick response.

ASSISTANT: Welcome, have a great day.