You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, How can I assist you?

USER: I want to change my existing reservation due to postpone of my document verification. Can you assist me?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your name to check the status of your reservation?

USER: Myself Matthew Lee.

ASSISTANT: Ok, please be on hold.

USER: Sure.

ASSISTANT: Thanks for the time. There is no active reservation found with your name, to cancel it.

USER: Ok, thank you.

ASSISTANT: Thank you for approaching us.