When you select 'Modify' and 'Modify attributes of variables...' from the File pull-down menu on the main window, the Contents window for the current data set is brought up. The Contents window includes a scrollable list of the data set's variables, showing each variable's name, type (numeric or character), length, label, format, and informat. You can modify the value in any yellow field (if you have a monochrome terminal, you can find the modifiable fields by seeing which fields you can tab to).
For attribute information on the data set as a whole, select the button from the Contents window. Again, some of the data set attribute information is modifiable.
If you do not have write access to the current data set, or if it is a view, the Contents window appears in browse mode.
Information in the main window may be updated after you modify variable attributes.