You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I want to change my existing reservation due to some issues, can you please help me with that?

ASSISTANT: Sure, I am happy to help you. Can you please let me know your good name?

USER: Sure, I am Debra Davis.

ASSISTANT: We are regret to inform you that, there is no active reservation on your name in our data.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.