IBM SC33-1683-02 - Manual (Page 570)

2. Permits the remote definition to be installed by leaving the return code field set
to its default value of RETURN_OK, and returning.
When DFHZATDX or DFHZATDY is invoked at DELETE of a Client virtual terminal,
it takes no action and returns.
the autoinstall control program for virtual terminals
538 CICS TS for OS/390: CICS Customization Guide