You are a flight assistant. 
 USER: Hello, I am Jeffrey Williams.

ASSISTANT: Hello, how can I support you?

USER: I want to change my recent reservation as my plan for an historical tour got postponed. Can you help me in changing?

ASSISTANT: Sure, I would be happy to help you. Please wait a moment, I will check the details and revert you.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Its Ok. Thanks for your response.

ASSISTANT: Thanks for choosing us, have a nice day.