i have this as a batch file,

save the below into a batch file, then run the batch file rm_unmount.bat "application set name" "job name" you will need to change the items in bold for your own environment.

@echo off
rem - rm_unmount.bat
rem - Unmount an RM replica
rem - Command line arguments
rem -   Arg 1 = RM application set name
rem -   Arg 2 = RM job name

rem - Save the current environment variables
rem - and enable command extensions
setlocal
setlocal enableextensions
setlocal enabledelayedexpansion

rem - Command line arguments
set APPSET=%1
set JOB=%2
if not defined APPSET (
echo ABORT
echo Application Set not specified on the command line
exit /b 1
)
if not defined JOB (
echo ABORT
echo Job not specified on the command line
exit /b 1
)

rem - The RM environment
set RMCLI="C:\Program Files (x86)\EMC\rm\gui\rmcli.bat"
set SERVER=RM server NAME

set PORT=65432
set USER=Administrator
set PASSWORD=password

set COMMAND=c:\temp\rm_unmount_%JOB%_command.txt
set OUTPUT=c:\temp\rm_unmount_%JOB%_output.txt
set TEMP1=c:\temp\rm_unmount_%JOB%_temp1.txt
set TEMP2=c:\temp\rm_unmount_%JOB%_temp2.txt

echo.
echo Unmount and delete an RM replica
echo Application Set = %APPSET%
echo Job = %Job%

echo.
echo List all replicas for the Applicaton Set

if exist %COMMAND% del %COMMAND%
if exist %OUTPUT% del %OUTPUT%
echo if-not connect host=%SERVER% port=%PORT% then exit 1 >>%COMMAND%
echo if-not login user=%USER% password=%PASSWORD% then exit 1 >>%COMMAND%
echo list name=/Application Sets/%APPSET%/Replicas recursive=yes >>%COMMAND%
echo exit 0 >>%COMMAND%
call %RMCLI% file=%COMMAND% >%OUTPUT% 2>&1
echo ExitCode = %ERRORLEVEL%
if %ERRORLEVEL% neq 0 (
echo ABORT
type %OUTPUT%
exit /b 1
)
type %OUTPUT%

echo.
echo List replica details and unmount

rem - Select each replica line from the output and save this to a temp file
rem - Then call the unmount subroutine for each line in the temp file
set COUNT=0
type %OUTPUT% | findstr /R /C:"^/" | findstr /R /C:":" >%TEMP1%
rem - type %TEMP1%
for /f  "tokens=*" %%R in (%TEMP1%) do (
                call :UNMOUNT "%%R"
)
echo.
echo Replicas unmounted = %COUNT%

exit /b 0

rem -----------------------------------------------------------------------
rem - End of main routine
rem - Start of subroutines
rem -----------------------------------------------------------------------

rem -----------------------------------------------------------------------
rem - Subroutine to unmount a replica
rem -----------------------------------------------------------------------
:UNMOUNT

set REPLICA=%~1

echo.
echo ********************
echo Replica = %REPLICA%
echo ********************

echo.
echo Get replica details
if exist %COMMAND% del %COMMAND%
if exist %OUTPUT% del %OUTPUT%
echo if-not connect host=%SERVER% port=%PORT% then exit 1 >>%COMMAND%
echo if-not login user=%USER% password=%PASSWORD% then exit 1 >>%COMMAND%
echo list-properties name=%REPLICA% >>%COMMAND%
echo exit 0 >>%COMMAND%
call %RMCLI% file=%COMMAND% >%OUTPUT% 2>&1
echo ExitCode = %ERRORLEVEL%
if %ERRORLEVEL% neq 0 (
echo ABORT
type %OUTPUT%
exit /b 1
)
type %OUTPUT%

rem - Check the replica is for this job
type %OUTPUT% | findstr /R /C:"^Replica Name:" | findstr /R /C:"%Job%" >nul
if %ERRORLEVEL% neq 0 (
echo.
echo Replica is not for this job
goto :EOF
)
echo.
echo Replica is for this job

rem - Check the replica is not a failed replica
type %OUTPUT% | findstr /R /C:"^Flags:" | findstr /R /C:"Failed" >nul
if %ERRORLEVEL% equ 0 (
echo.
echo Replica is a failed replica
goto :EOF
)
echo.
echo Replica is not a failed replica

rem - So far we have been using the full replica name
rem -  /Application Sets/ / /Replicas/
rem - The delete command requires just the part of the name
for /f "tokens=4 delims=/" %%R in ("%REPLICA%") do (
set REPLICA_DATETIME=%%R
)
rem echo %REPLICA_DATETIME%

echo.
echo Unmount replica

if exist %COMMAND% del %COMMAND%
if exist %OUTPUT% del %OUTPUT%
echo if-not connect host=%SERVER% port=%PORT% then exit 1 >>%COMMAND%
echo if-not login user=%USER% password=%PASSWORD% then exit 1 >>%COMMAND%
echo if-not unmount-replica name=%REPLICA_DATETIME% appset=%APPSET% then exit 1 >>%COMMAND%
echo exit 0 >>%COMMAND%
call %RMCLI% file=%COMMAND% >%OUTPUT% 2>&1
echo ExitCode = %ERRORLEVEL%
if %ERRORLEVEL% neq 0 (
echo ABORT
type %OUTPUT%
exit /b 1
)
type %OUTPUT%

echo.
echo Delete replica

if exist %COMMAND% del %COMMAND%
if exist %OUTPUT% del %OUTPUT%
echo if-not connect host=%SERVER% port=%PORT% then exit 1 >>%COMMAND%
echo if-not login user=%USER% password=%PASSWORD% then exit 1 >>%COMMAND%
echo if-not delete-replica name=%REPLICA_DATETIME% appset=%APPSET% then exit 1 >>%COMMAND%
echo exit 0 >>%COMMAND%
call %RMCLI% file=%COMMAND% >%OUTPUT% 2>&1
echo ExitCode = %ERRORLEVEL%
if %ERRORLEVEL% neq 0 (
echo ABORT
type %OUTPUT%
exit /b 1
)
type %OUTPUT%

set /a COUNT=%COUNT% + 1

goto :EOF