You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How exactly I can serve you the best today?

USER: I want to change my existing reservation, due to my trip with my friends has been postponed. Can you please help me?

ASSISTANT: Sure, I am happy to help you to change the ticket details once I have found your ticket. Can I know your name please?

USER: Sure, please check my reservation on the name of Anthony Mitchell.

ASSISTANT: Ok, wait for some time I will check the reservation on your name and get back to you.

USER: Sure, I will wait for your response.

ASSISTANT: We are sorry to say that, there is no active reservation found on your name.

USER: Ok, thanks for your assistance.

ASSISTANT: Thanks for reaching us, wish you a great day.