You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I need to modify my reservation as my schedule got postponed because my exams are going to schedule on those days. Can you please help me to modify my reservation which I have done on my name Samantha Nelson?

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

USER: Thank you for considering my request.

ASSISTANT: Please wait for a while. Sorry, there are no reservations found.

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

ASSISTANT: Thank you for choosing us.

USER: You are welcome.