You can edit the resource definitions using ESMAC, which provides a graphical user interface. For more information see the section Controlling CICS Resources in the chapter Administering MSS-enabled Enterprise Servers.
Alternatively, you can edit them using a text editor, but to do this, you first need to export the resource definition tables from the dfhdrdat file, and when you have finished editing, you need to import the tables back again. For more information about importing and exporting resources see the section Exchanging Resource Definitions Between Resource Definition Files .