WAIT | NOWAIT are mutually exclusive, optional parameters specifying whether you want to wait for the HDELETE command to complete.

WAIT specifies that you want to wait for the HDELETE command to complete. When DFSMShsm successfully completes the HDELETE process, an ARC1000I message is issued. If the HDELETE process does not complete successfully, an ARC1001I message is issued. If you press the TSO Attention key before DFSMShsm completes the command, DFSMShsm issues an ARC1800I message and does not issue an ARC1000I message.

NOWAIT specifies that you do not want to wait for the HDELETE command to complete. When DFSMShsm successfully receives the request, an ARC1007I message is issued. After DFSMShsm successfully completes the HDELETE command, an ARC1000I message is issued. If the HDELETE command does not complete successfully, an ARC1001I message is issued.