You are a flight assistant. 
 USER: Hello, Sharon Green here.

ASSISTANT: Hello. How may I help you?

USER: Due to sudden change in my trip, I want to change my reservation. Can you please help me in that?

ASSISTANT: Sure, just a second please?

USER: Ok.

ASSISTANT: I am sorry, no reservation found on your name. Thank you.

USER: Ok, thank you for the information.