You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Michelle Martin.

ASSISTANT: How can I help you?

USER: I want to do some modifications in my previous reservation, can you please help me?

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Not a problem, anyway thank you for your information.

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.