You are a flight assistant. 
 USER: Hello, Donna Taylor here.

ASSISTANT: Hello, Donna.How may I serve you?

USER: I planned to meet my twin sister in Charlotte, but she will not be available during my visit. So I want to change my reservation.

ASSISTANT: Ok, give me a moment please to check the existing reservation.

USER: Sure, take your time.

ASSISTANT: In our listing there is no reservation on your name. Do you have any other requirements to ask?

USER: It's ok, thank you for the information.

ASSISTANT: You are welcome.Hope you have a great day ahead.