Before an application (that is a member of a generic resource) issues CLOSE ACB, all LU sessions should be terminated. The application program issues CHANGE OPTCD=ENDAFFIN, which allows VTAM® to end the affinity between the application program and the LU. After all sessions with LUs have been terminated, and the generic resource application program has terminated affinities with all LUs, the application can issue CLOSE ACB. If the application issues CLOSE ACB without terminating the LU-to-application affinities, the affinities may persist.

VTAM also provides the CHANGE macro with OPTCD=ENDAFFNF (End Affinity Force). This option allows the affinity with a specific LU to be terminated immediately, even if sessions are still active.