You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how best can I support you?

USER: I want to change my recent reservation due to postpone of my exams. Can you help me in that?

ASSISTANT: Sure, please share your good name?

USER: Robert Smith here.

ASSISTANT: Please stand by.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no active reservation found with the given name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you.