You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am planning to change an existing reservation, due to health issue. Can you please help me out?

ASSISTANT: Sure, I am here to help you with your concern. May I know your name please?

USER: My name is Brian Collins.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Brian Collins, no reservation has been found on your name in our database.

USER: That's fine, thank you for your help.

ASSISTANT: Thank you for reaching us.