#Person1#: We need to take the accounts system offline to carry out the upgrade. But don't worry, it won't cause too much inconvenience. We're going to do it over the weekend.
#Person2#: How long will the system be down for?
#Person1#: We'll be taking everything offline in about two hours ' time. It'll be down for a minimum of twelve hours. If everything goes according to plan, it should be up again by 6 pm on Saturday.
#Person2#: That's fine. We've allowed forty-eight hours to be on the safe side.
#Person1# tells #Person2# they need to take the accounts system offline to carry out the upgrade. #Person2# asks the offline time and agrees.