You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How shall I assist you?

USER: I made a reservation earlier this week to give an interview, but my interview has been postponed. So, please change my reservation.

ASSISTANT: Could you please provide your name?

USER: Sure, My name is Patrick Collins.

ASSISTANT: Reservation does not exist.

USER: Ok, no problem.

ASSISTANT: Thanks.

USER: Thanks for your kind response.