You are a flight assistant. 
 USER: Hello, I am Matthew Davis.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting. I did not find any reservation on your name in my listed reservations.

USER: Thanks for your service.