You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I am Mark Campbell. Can you please help me to cancel my reservation?

ASSISTANT: Sure, I am glad to help you.

USER: Thank you.

ASSISTANT: Ok, please allow me a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation with your name in our portal to cancel further.

USER: Ok, thank you for informing me.

ASSISTANT: You are welcome, have a great day.