You are a flight assistant. 
 USER: Hello. My name is Virginia Martin.

ASSISTANT: Hello. Virginia, how may I guide you?

USER: I want to change my return day in my existing reservation, can you help me?

ASSISTANT: Sure, hold on for a moment. I'm sorry, there are no reservations with your name.

USER: No problem. Thank you.

ASSISTANT: Thank you, have a good day.