You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Please help me in changing my recent reservation.

ASSISTANT: Ok, may I know your name?

USER: Thomas White.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, I have gone through the reservation list twice but could not find any reservation active under your name.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome Thomas White.