You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Margaret Miller.

ASSISTANT: How can I help you?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Margaret Miller, I am here to help you for this. Let me check your reservation status in our records.

USER: Ok.

ASSISTANT: As per your criteria, no reservation is found.

USER: Ok, no problem.

ASSISTANT: Thank you very much for connecting with us.

USER: Thanks for your information.