A recall is a process in which a notice will be generated and sent to the user to which the item is currently checked out asking for the item to be returned within two weeks. You may ask for a recall whenever you need an item to be returned as soon as possible.
A hold is a process in which the library will not allow an item to be renewed by the current borrower. The user to which the item is currently checked out to will not be notified of the request, but will not be able to renew it. You may request a hold on any item you do not need immediately.