You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Lisa Mitchell.

ASSISTANT: Lisa, how may I assist you today?

USER: Can you please change my existing reservation? because my sister reserved me a ticket with a wrong airport and location.

ASSISTANT: Sure, I will help you, wait for a moment please to check your reservation status.

USER: Ok.

ASSISTANT: Lisa, in my database I did not found any reservation with your name.

USER: No issue, thank you.

ASSISTANT: My pleasure, have a good day.