You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I need to cancel my reservation due to some personal issues.So can you help me with cancellation of my reservation?

ASSISTANT: Sure, I will help you to cancel your reservation.

USER: Thank you.

ASSISTANT: Ok, please let me know your name to check your previous reservation.

USER: I am Sandra Miller.

ASSISTANT: Sorry, no reservation found on your name to cancel your reservation.

USER: No problem, thank you for the information.

ASSISTANT: Welcome, have a nice day.