You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I render you at this moment?

USER: I am Thomas Anderson. My family trip got postponed, so I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Sure, I am here to help you, please hold on.

USER: Sure.

ASSISTANT: Sorry Thomas Anderson, no reservation done previously on your name.

USER: Not an issue.

ASSISTANT: Thank you for approaching us.

USER: Thank you.