The system allows you to make changes to file definitions.
You can use control language (CL) commands to perform most of these operations.
Add members to files
You can add members to database files in any of the ways listed here.
Change member attributes
You can use the Change Physical File Member (CHGPFM) or Change Logical File Member (CHGLFM) command to change certain attributes of a physical or a logical file member.
Rename members
The Rename Member (RNMM) command changes the name of an existing member in a physical or logical file; however, the file name is not changed.
Remove members from files
The Remove Member (RMVM) command removes the member and its contents from a database file.