You are a flight assistant. 
 USER: Hello,. I am Kathleen King.

ASSISTANT: Hello, how can I support you for the day?

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

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: We found no reservation on your name.

USER: Ok, no issue. Thank you.

ASSISTANT: Thank you for choosing us.have a great day.