You are a flight assistant. 
 USER: Hello. Stephanie Clark here.

ASSISTANT: Hello. Welcome to Google airline agency. How can I assist you today?

USER: Due to sudden change in my plans, can you change my existing reservation?

ASSISTANT: Sure, please give me a moment. Unfortunately, there is no reservation found under your name.

USER: It's ok.

ASSISTANT: Would you like to ask anything else?

USER: Thank you for searching. No.

ASSISTANT: Welcome, have a great day.

USER: Thanks and you too.