You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: For a safe side I reserved a plane ticket to my destination in advance but as my health is not good to catch that plane please cancel my ticket.

ASSISTANT: Sad to hear that. Sure, may I know your name?

USER: My good name is Christopher Clark.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: It's ok. Thank you for your response.

ASSISTANT: Take care of your health. Thank you for picking us.