You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: On which name can I proceed for cancelling?

USER: Please change my reservation which is on the name Shirley Mitchell.

ASSISTANT: I am sorry no reservation found on your name .

USER: No problem, thanks for checking.

ASSISTANT: Thank you for choosing us.