You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Charles Clark.

ASSISTANT: How can I aid 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: Please wait for a while.

USER: Ok.

ASSISTANT: We are sorry to inform you that there is no reservation found with your given name.

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

ASSISTANT: Thank you.