You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you for the day?

USER: I have made a reservation earlier to reach Los Angeles, but due to some issues I need to change my reservation, so please help me.

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May, I know your good name?

USER: Sure, I am Dennis Miller.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: No worries, thank you.

ASSISTANT: Thank you for reaching us.