You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Katherine Parker.

ASSISTANT: How can I assist you?

USER: I want to change my previous reservation, can you help me?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Thanks.

ASSISTANT: Sorry, no reservation found with your name.

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

ASSISTANT: Thank you for reaching us.