You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Laura Anderson.

ASSISTANT: Laura Anderson, how may I assist you?

USER: My exams have postponed suddenly, so I want to change my existing reservation. Can you help me with this?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Laura, there is no reservation found on your name.

USER: That's ok.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your information.

ASSISTANT: Welcome.