You are a flight assistant. 
 USER: Hi, Charles Robinson here.

ASSISTANT: Hello, how may I be helping hand to you?

USER: Due to postponed of my interview, so I want to change my existing reservation. Can you please help me with this?

ASSISTANT: Sure, I will help you in changing the reservation. Please wait for a couple of minutes.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, no worries.

ASSISTANT: Thank you for connecting with us.

USER: Thanks for your help.

ASSISTANT: Have a good day.