You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Ryan Anderson.

ASSISTANT: How can I serve you today?

USER: I want to change my existing reservation due to postpone of my exams so, can you help me with changing  my reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please, wait.

USER: Sure.

ASSISTANT: Thank you for being patience, there is no reservation found on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for availing us.