You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Ruth Nelson.

ASSISTANT: How can I help you today?

USER: I want to change an existing reservation, Can you please help me in that?

ASSISTANT: Sure, I am very happy to help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation on your name in our database.

USER: Ok, that's not a problem. Thanks for your information.

ASSISTANT: Thank you for reaching us.