You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my reservation, can you help me?

ASSISTANT: Ok, please let me know your name to change the reservation.

USER: I am Patrick Lewis.

ASSISTANT: Sorry, there are no reservations been found on your name to change it.

USER: No problem, thanks for checking.

ASSISTANT: Ok, thank you for choosing our agency.