You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: Due to health issue I want to change my existing  reservation. Can you please help me?

ASSISTANT: Sure, please mention your name to proceed further?

USER: George Edwards.

ASSISTANT: Ok, please hold a moment, let me check your reservation and let you know.

USER: Sure.

ASSISTANT: Thanks for your time, sorry, unfortunately no reservation found with your name.

USER: Ok, no problem. Thanks for your support.

ASSISTANT: Thanks for your interest, have a great day ahead.