You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my an existing reservation due to postpone of my exam dates. Can you please help me with this?

ASSISTANT: Sure, can I have your name please?

USER: My name is Ashley Brown.

ASSISTANT: There is no active reservation on your given name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.