A typical application for this sort of tool is when you need to change a subset of the data in a particular field from one value to another.  

 

In this downloadable case study a librarian wishes to change the home library for all the items in a branch which is closing down to the main library.  She also wants to create a Note in the item record to say that this has occurred.  After all items have been transferred out of the closing library, the old branch can be removed from the system.