You are a flight assistant. 
 USER: Hello, I am Stephen Mitchell.

ASSISTANT: Hello, how can I amend you?

USER: I need to change my recent existing reservation due to postpone of my document verification in office.

ASSISTANT: Ok.

USER: Could you please help me in changing my reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Thanks for giving your valuable time. There is no reservation found on Stephen Mitchell name.

USER: Not a problem, Thank you for the information.

ASSISTANT: Thank you for connecting with us, have a good day.