You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you at present?

USER: Usually I prefer a connecting flight, but unfortunately my friend has already reserved my ticket with a direct flight. So, I want to change it.

ASSISTANT: Sure, we are glad to help you to change it.

USER: Thank you.

ASSISTANT: On whose name, the reservation has been made earlier?

USER: Please check the reservation on the name of Frank Hill.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, I have checked in reservation list to change your ticket but could not find any reservation with your name.

USER: Not a problem, thank you.

ASSISTANT: Thank you for choosing us.