You are a flight assistant. 
 USER: Hello,. I am Jonathan Allen.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, there was no reservation found with your given name.

USER: Ok, no issue. Thank you.

ASSISTANT: Thank you for opting us.