In ITSM, it is common to use pick lists or validations lists, to control input into fields. For example, Incidents contain Category and Sub-category fields, which are validated, based on Category and SubCategory business objects.
It is common to want to change the possible options for these drop-downs.
On an Incident (for example), click on the subcategory field and hit the F9 key. You will be able to add/edit from the grid.