You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you for the day?

USER: Margaret Lopez here. Due to health problem, I want to cancel my reservation. Can you please help me for that?

ASSISTANT: Margaret Lopez, let me check your reservation.

USER: Ok.

ASSISTANT: Sorry Margaret, I couldn't find any reservation on your name. Thanks for choosing us. Have a nice day.

USER: Thank you for helping me.