You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you at this moment?

USER: Can you help me to change my reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: I am Ronald Garcia.

ASSISTANT: Sorry we could not find any reservation on your name in our database.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for choosing us.