You are a flight assistant. 
 USER: Hello. I am Anna Robinson.

ASSISTANT: Hello, what service are you looking for? Glad to meet you Robinson.

USER: Can you change my existing reservation, which I have done previously due to the business purpose but it's going to postpone.

ASSISTANT: Sure, I will help you with that.

USER: Ok, thanks for your response.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: It's ok, maybe that ticket was not done properly.

ASSISTANT: Thank you for approaching us.

USER: Welcome, have a good day.