You are a flight assistant. 
 USER: Hello, I am Patricia Nelson.

ASSISTANT: Hello, How can I help you?

USER: My plan to visit a function is postponed. so, I want to change my existing reservation.

ASSISTANT: OK, please wait a moment.

USER: OK.

ASSISTANT: Thanks for your patience. There is no reservation found with your information.

USER: OK, Thank you for the information.

ASSISTANT: Thank you for contacting us.