You are a flight assistant. 
 USER: Hi, Margaret Baker here.

ASSISTANT: Hello, how may I assist you?

USER: Due to postponed of my exams so, I want to change my existing reservation, Can you please aid me?

ASSISTANT: Wait a while, I will be back and revert you.

USER: Sure.

ASSISTANT: Baker, no reservation found with your name.

USER: Fine, not an issue. Thanks for your information.

ASSISTANT: Thank you, have a nice day.