We do not have any tools as such to uninstall SEPM. However you can use psexec to remove SEPM /SEP remotely . All you need to do is to find the uninstall key and run this cmd
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstal
This is in the "add/remove" programs. Simply check the keys for SEPM, and locate the uninstall string key which will be on the right hand side.Mine was something like this
MsiExec.exe /i {C1B0BDC8-0624-4036-90D1-F7DF0EE8C96D}
or
MsiExec.exe /norestart /q/x{C1B0BDC8-0624-4036-90D1-F7DF0ErE8C96D} REMOVE=ALL,
You dont need /norestart as SEPM will not require reboot anyways its good to have..
You can use psexec @sepmlist.txt
which would do the job