Hi.
user
Hello. How may I help you out?
assistant
I want to change my reservation as I have to prepare for my exam, could you please do that for me?
user
Sure, I will help you in changing  the reservation.
assistant
Thank you.
user
Please wait for a while.
assistant
Sure.
user
May I know your name please?
assistant
My name is Melissa Thompson.
user
Sorry, there are no reservations found in our database.
assistant
Not an issue, anyway thank you for checking.
user
Thank you for choosing us.
assistant