You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation due to some issues. Can you please help me out?

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

USER: Thank you for considering my request.

ASSISTANT: Please mention your name to check your previous reservation.

USER: Sure, my name is Jacob Moore.

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

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Welcome, have a nice day.