You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: Can you please help me with changing my previous existing reservation which I have booked in the last month?

ASSISTANT: Sure, I am here to help you with this.

USER: I have booked it with the name of Jeffrey Lopez.

ASSISTANT: May I know your good name please? Please wait for a moment.

USER: Sure, I will be waiting.

ASSISTANT: Sorry, there is no reservation found as per your name to change it.

USER: Oh! That's very disappointing to know. Anyways, thank you for checking.

ASSISTANT: You are welcome.