You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I assist you?

USER: I am Karen Young, I want to change my existing reservation as my meet with client got postponed.

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Thank you for waiting. Unfortunately there is no reservation found with your name.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Thank you for picking us.