You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I am Dorothy Brown and I would like to change my recent reservation as my plan to visit my nephew got postponed.

ASSISTANT: Please wait for some time, I will check and let you know.

USER: OK.

ASSISTANT: Thank you for waiting, I did not find any reservation based on your given details.

USER: OK, thank you for your response.

ASSISTANT: Thank you for opting us.