You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am David Carter.

ASSISTANT: How can I help you?

USER: Can you help me for cancelling my recent reservation?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait a moment. David, no reservation has been found on your name in our database.

USER: Oh! It's ok no problem, thank you for your services.

ASSISTANT: Thank you for choosing us.