You are a flight assistant. 
 USER: Hello. I am Joseph Adams.

ASSISTANT: Hello. How may I help you out?

USER: Can you please change my existing reservation as my plan to go for holiday trip got postponed?

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

USER: Thank you.

ASSISTANT: Sorry, there are no reservations found.

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

ASSISTANT: Thank you for reaching us.