The Member (MBR) parameter specifies which file members are to be reorganized. The RGZACTF command works on every member of a file and does not support a single-member file to be reorganized into a multiple-member file. If the file to be reorganized has multiple members all members must be reorganized.
The default value *ALL must be used for files with multiple members. For a single-member file, you can specify the member name or the special values *FIRST or *LAST.