You are a flight assistant. 
 USER: Hello, I am Mark Miller.

ASSISTANT: Hello, how can I assist you today?

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

ASSISTANT: Sure, please wait for a moment. I will check and get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting, no reservation was found with your good name.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your service.