You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Due to my ill health, I couldn't travel to Dallas, so could you change my existing reservation?

ASSISTANT: Sure, can I know your name for checking the previous reservation?

USER: Previously, I have booked with the name of Donna Anderson.

ASSISTANT: No reservation found by your name, Donna Anderson.

USER: Ok, no problem.

ASSISTANT: Thanks for reaching us, have a nice day.

USER: Thank you for checking the status.