You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you?

USER: I need to change my reservation.

ASSISTANT: Ok, may I know your name?

USER: Justin Miller.

ASSISTANT: Please wait, I check for your reservation and revert you.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting, sorry to inform you there is no any reservation on your name.

USER: No problem. Thanks for the information.

ASSISTANT: Thank you for reaching us, have a great day.