You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: My name is Sarah Johnson. I need your help in changing my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you Sarah, in change existing reservation. Please wait a moment. No reservation available on your name Sarah.

USER: It's ok. Thank you.

ASSISTANT: Thank you for contacting us, have a good day.