You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you now?

USER: Benjamin Nelson here. I would like to change my reservation. As my trip plans have been changed.

ASSISTANT: Ok, please allow me to check with your previous booking.

USER: Sure, take your time.

ASSISTANT: Benjamin Nelson, there is no flight reservation in our database.

USER: No issue, thank you for the assistance.

ASSISTANT: Thank you for choosing our assistance. Have a nice day.