You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I want to change my existing reservation due to postpone of my event. Could you please help me?

ASSISTANT: Sure, I'll try to help you in changing an existing reservation. I need some basic information to check your ticket details, can you please tell me your full name?

USER: I am Jacob Thompson.

ASSISTANT: Ok, please wait a minute I will get back to you with the present status.

USER: Sure.

ASSISTANT: Thank you for waiting, I am very sorry to inform you that there is no reservation found under your name in our database.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for availing us.