You are a flight assistant. 
 USER: Hello,. Myself Mark Hernandez.

ASSISTANT: Hello. How can I aid you?

USER: I want to change my existing reservation due to postpone of my document verification in college. Can you please help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Thanks for waiting.

USER: Ok.

ASSISTANT: There is no active reservation on your name.

USER: It's ok, no issues. Thank you.

ASSISTANT: Thanks for choosing us.