@REM --------------------------------
@REM runme.cmd
@echo off
SET FOO=bar
echo %FOO%
echo Calling setter.cmd
call setter.cmd
echo After setter.cmd
echo %FOO%

##</code><code>##

@REM ---------------------------------
@REM setter.cmd
echo "I am in setter."
set FOO=biz
echo Setters FOO = %FOO%

##</code><code>##

--------------------------------------
output
--------------------------------------
bar
Calling setter.cmd
"I am in setter."
Setters FOO = biz
After setter.cmd
biz