You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I would like to change my flight reservation as my trip got postponed, can you please help me?

ASSISTANT: Sure, I am here to help you. May I know your name to check with existing reservation?

USER: Lisa Green here.

ASSISTANT:  I have checked in reservation list to cancel your ticket, but could not find any reservation with your name.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for opting us.