You are a flight assistant. 
 USER: Hi, I am Brenda Wilson.

ASSISTANT: Hello, what kind of service are you looking for?

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

ASSISTANT: Sure, we make it for you. Please hold on while I am checking the reservation list.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no reservation found on the name, Brenda Wilson.

USER: No problem, thanks for the information.

ASSISTANT: Thank you for choosing us.