You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I render you today?

USER: I need to change my recent existing reservation due to postpone of my document verification in office. Can you help me to change an existing reservation?

ASSISTANT: Sure, we are here to make your work ease.

USER: I am Gary Harris.

ASSISTANT: May I know your name to check your details in our database?

USER: I made a reservation on this name Gary Harris.

ASSISTANT: Ok, please wait for a minute.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no reservation found on your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for opting us.