You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am David Parker.

ASSISTANT: David, how can I assist you today?

USER: I am planning to cancel my recent reservation, due to health issue. Can you please cancel my ticket?

ASSISTANT: Sure, I will help you David. I will check your reservation details and get back to you.

USER: Sure, take your own time.

ASSISTANT: David, I have not found any reservation by your name.

USER: Thank you for your help.

ASSISTANT: Thank you very much for contacting us.