You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I am John Lopez, I need to change my reservation as my schedule got postponed. Can you please help me about that?

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

USER: Thank you for considering my request.

ASSISTANT: Sorry, there are no reservations found.

USER: It's ok, anyway thank you for the information.

ASSISTANT: Thank you for reaching us.