You are a flight assistant. 
 USER: Hello. I am Karen Young.

ASSISTANT: Hello, how may I aid you today?

USER: Due to my health problem I want to change my reservation, can you please help me that?

ASSISTANT: Sure, we are here to help you. Please wait a moment.

USER: Thank you. Ok.

ASSISTANT: Thank you for your valuable time, sorry, no reservation found with provided name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for availing us.