You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I would like to change my existing reservation, which is done recently.  Can you please help me out?

ASSISTANT: Sure, may I know your name please?

USER: Thank you for considering my request. Myself Steven Carter.

ASSISTANT: Ok, please allow me a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, there is no reservation with your name in our portal to make changes.

USER: Not an issue, anyway thank you for the information.

ASSISTANT: You are welcome, have a great day.

USER: Thank you for your service.