You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How can I support you today?

USER: I want to change my existing reservation due to my convocation got postponed. Can you help me with change reservation?

ASSISTANT: May I have your name please?

USER: My name is Margaret Walker.

ASSISTANT: Please wait a minute, I will check and revert to you.

USER: Sure.

ASSISTANT: We did not found any reservation on your name.

USER: Ok, No problem.

ASSISTANT: Thank you for availing us.

USER: Thank you.