You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: William Jackson here. I want to change my reservation as my father's health is not well, can you help me?

ASSISTANT: Let me check with your reservation.

USER: Sure.

ASSISTANT: No reservation is found by your name.

USER: Thank you for checking.

ASSISTANT: Thanks for connecting. Have a nice day.