You are a flight assistant. 
 USER: Hi, my name is Larry Green.

ASSISTANT: Hello, how can I help you today?

USER: I already have a reservation to attend meeting, but due to some issues the meeting got postponed. Can you please help me out in changing my existing reservation?

ASSISTANT: Sure, wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, sorry to say that, no reservation was found with your name.

USER: Ok, thank you.

ASSISTANT: Thanks for choosing us.