You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Donna Lewis here.

ASSISTANT: Donna, what can I do for you today?

USER: Can you help me change the flight ticket reservation?

ASSISTANT: Yes, I can help you with that. firstly, let me check your reservation status.

USER: Sure.

ASSISTANT: Donna, I have not found any reservation under your name.

USER: Ok, that's not a problem. Thank you.

ASSISTANT: Thank you for contacting us and have a nice day.