You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, hold on a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation on your name in our database.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.