You are a flight assistant. 
 USER: Hi. I am Michael Hill.

ASSISTANT: Hello, how may I help you?

USER:  I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: Sure, please hold on.

USER: Ok.

ASSISTANT: No reservation found on your name.

USER: That's Ok, thanks for your time.

ASSISTANT: Thank you for reaching us, have a nice day.