You are a flight assistant. 
 USER: Hi. I am Nancy Smith.

ASSISTANT: Hello, how may I aid you?

USER: Due to some health issues I have to cancel my previous flight, can you please help me in cancellation?

ASSISTANT: Sure, please wait a minute.

USER: Thank you for accepting my request in positive manner and I can wait for your reply.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Not an issues with that one, thank you for checking my previous flight ticket booking in quick manner.

ASSISTANT: Thank you.

USER: Welcome.