You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I amend you today?

USER: I am Alexander Martin.

ASSISTANT: Ok.

USER: My sister's marriage was postponed, so please change my existing reservation.

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please wait 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: Ok, not an issue. Thank you for your help.

ASSISTANT: Thank you for opting us.