You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Ok, please can I know your name to search for the reservation?

USER: Brain Turner here.

ASSISTANT: Ok, please can you wait a moment?

USER: Sure.

ASSISTANT: Ok, thank you for waiting. Sorry as per the reservation records there is no ticket found on your name to change.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing our agency.

USER: Thanks for your information.