You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I have to change my ticket reservation, can you do that one for me?

ASSISTANT: Sure, I am ready to help you with changing your reservation.

USER: Thank you.

ASSISTANT: Can I have your name please for checking your reservation status?

USER: Sure, my name is Sarah Allen.

ASSISTANT: Ok, please wait a moment.

USER: Ok, carry on.

ASSISTANT: Sorry Sarah Allen, no reservation has found under your name to change.

USER: Ok, not an issue with that one. Thank you for your help.

ASSISTANT: Thank you for choosing us, have a good day.