I tried:

symconfigure -sid xxxx set dev 020EA device_name=to_be_deleted_REQ123;

'set': Invalid action.
dynamox 
 

Following are all information related to versions:

    Microcode Version (Number) : 5876 (16F40000)
     Microcode Registered Build : 18
     Microcode Date : 02.11.2016
     Microcode Patch Date : 02.11.2016
     Microcode Patch Level : 288
     Symmwin Version : 195
     Enginuity Build Version : 5876.288.195
     Symmetrix CLI (SYMCLI) Version : V8.1.2.0 (Edit Level: 2112)
     Built with SYMAPI Version : V8.1.2.0 (Edit Level: 2112)
     SYMAPI Run Time Version : V8.1.2.0 (Edit Level: 2112)