You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Paul Collins.

ASSISTANT: Paul Collins, how may I assist you with today?

USER: Due to some urgent meeting, I am going to change my existing reservation. Can you please help me for this?

ASSISTANT: Sure, I will help you. Please allow me a minute while I check with it.

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

ASSISTANT: I regret to bring this to your notice that there is no reservation on your name.

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

ASSISTANT: Thank you for understanding. Thank you for reaching us, have a great day.