You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: Due to some sudden change in my schedule, I want your help to modify my existing reservation. Can you please help me with that?

ASSISTANT: Sure, please provide you name I will help you out?

USER: My name is Brian Lopez.

ASSISTANT: Sorry Brian, there is no reservation found on your name.

USER: That's ok, may be something went wrong while I was doing my reservation.

ASSISTANT: Yes, may be.

USER: Anyways, thank you for your time.

ASSISTANT: My pleasure, thank you for reaching us.