You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Patricia Smith. I need to change my existing reservation, as my business meeting with my partners got postponed. Could you help me in changing my existing reservation?

ASSISTANT: Sure, we are here to help you. Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, no issues. Thanks for your help.

ASSISTANT: Thank you for choosing us.