You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Brandon Phillips.

ASSISTANT: How may I assist you?

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

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please be on hold I will the reservation list and let you know the status.

USER: Sure.

ASSISTANT: Thank you for your time. Sorry, we could not find any reservation in your name.

USER: It's ok, no problem. Thanks for your kind response.

ASSISTANT: Thank you for opting us.