You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. May I know your good name, Please? How may I assist you for the day?

USER: I want to change my existing reservation due to change of my friends convocation.

ASSISTANT: OK.

USER: Sure, I am Eric Young.

ASSISTANT: We are very sorry to inform you that, There is no reservation found on Eric Young.

USER: Ok, no problem.

ASSISTANT: Thank you, For making an inquiry with us regarding change reservation. Have a great day.

USER: Thank you for your response.