You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Mark Turner here.

ASSISTANT: How may I guide you today?

USER: I want to cancel my reservation, due to some health problem. Can you help me?

ASSISTANT: Sure, I will help you with that.

USER: Thank you for your positive response.

ASSISTANT: Please wait for a minute.

USER: Sure, I will wait for your information.

ASSISTANT: I am sorry to say that there is no reservation found under your details.

USER: Not a problem, thank you for searching.

ASSISTANT: Thank you for reaching us, have a great day.