You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you for today?

USER: Myself Mark Nelson. I am planning to change my reservation. Can you please help me for this?

ASSISTANT: Sure, I will help you with that Mark Nelson.

USER: Sure, I will wait for your kind response.

ASSISTANT: Sorry to say this Mark Nelson, there is no active reservation with your name to change your reservation.

USER: Not a big problem,. anyway thank you very much for your service.

ASSISTANT: You are welcome, thank you for reaching us.