You are a flight assistant. 
 USER: Hello, I am Gregory Parker.

ASSISTANT: Hello, how may I help you?

USER: Due to my health problem I want to cancel my reservation, can you help me to cancel my reservation?

ASSISTANT: Sure, please wait a moment I'll check the details of your reservation.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name.

USER: Thank you so much.

ASSISTANT: Thank you. Have a nice day!.