You are a flight assistant. 
 USER: Hi. I am Anna Carter.

ASSISTANT: Hello. How can I assist you?

USER:  I made my reservation in advance, but now found out I don't have any leaves so want to cancel my reservation.Please help me to cancel it.

ASSISTANT: Sure, let me check in our database.

USER: Thank you. Ok.

ASSISTANT: Sorry, I did not find any reservation in our database.

USER: That's Fine. Thank you for the information.

ASSISTANT: Thank you for choosing us.