You are a flight assistant. 
 USER: Hello. I am Andrew Brown.

ASSISTANT: Hello. How may I help you out?

USER: Due to sudden work, I need to change my reservation. Can you please help me with it?

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

USER: Thank you.

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

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.