You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I would like to cancel my reservation which is done recently due to some problems, can you please help me in this condition?

ASSISTANT: Yes, I can help you.

USER: Thank you.

ASSISTANT: Can I know your name for checking your previous reservation?

USER: Sure, my name is Mark Walker.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: That's ok, thank you for your service.

ASSISTANT: Thank you for consulting us.