You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you out?

USER: I am Stephen Lopez. I need to amend my reservation, can you help me out?

ASSISTANT: Sure, I will help you in changing the ticket.

USER: Thank you.

ASSISTANT: Sorry, there are no reservations found in our database.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.