You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Can you help me to change my reservation?

ASSISTANT: Sure, please provide your name to fetch your ticket from our database.

USER: I am Sandra Hill.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: We regret to inform you that there is no active reservation found on your name.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for contacting us.