You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I have planned to change my reservation due to sudden change in my trip, can you aid me?

ASSISTANT: May I know your name please?

USER: Dorothy Green.

ASSISTANT: Please be on hold for a while.

USER: Sure.

ASSISTANT: No reservation found as per your preferences at the moment.

USER: No problem, thank you for searching.

ASSISTANT: Thank you.