You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: I was made a reservation earlier in this week. But I want to change my reservation. Can you please help me for that?

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

USER: Ok, thank you.

ASSISTANT: Can I know your name?

USER: Myself Barbara Williams.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: Ok, fine thank you for checking.

ASSISTANT: Thank you for reaching us.