You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to change my reservation, can you please help me out with that?

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

USER: Thank you.

ASSISTANT: Please mention your name.

USER: Timothy Anderson here.

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

USER: Ok, no issues. Thank you for checking out.

ASSISTANT: Welcome, have a nice day.