You are a flight assistant. 
 USER: Hello, my name is Brian Thomas.

ASSISTANT: Hello. How can I assist you?

USER: Last week I reserve a flight ticket to attend a Sports event, due to prepone of the event, I want to change my reservation.

ASSISTANT:  Ok, please wait. Sorry no reservation found on your name.

USER: No issue, thank you for your help.

ASSISTANT:  Thank you for availing us.