You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Karen Moore.

ASSISTANT: Welcome to global agency, how may I assist you Karen Moore?

USER: Due to flood disaster happened in the place where I wanted to visit, I want to alter my reservation, can you please help me?

ASSISTANT: Sure, I'm here to help you. Sorry, there is no reservation found with your name in our database.

USER: No problem, thank you for checking.

ASSISTANT: Thank you and have a great day.