You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Ashley Walker. I need to change my recent reservation due to postpone of my exam.

ASSISTANT: Sure, I am oblige to help you. Please wait for a moment.

USER: Could you please help me in doing that? Sure.

ASSISTANT: Sorry, there is no reservation found for the user name in our data base.

USER: No problem, thank you for your information.

ASSISTANT: You are welcome.