You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Sandra Mitchell here.

ASSISTANT: How can I assist you now?

USER: I would like to cancel my recent reservation due to my health issue. Can you help me?

ASSISTANT: I can help you with that.

USER: Thank you.

ASSISTANT: Sorry Sandra, there is no reservation found on your name in my database.

USER: It's ok, no problem. Thank you for checking.

ASSISTANT: You are welcome. Thank you for choosing us.