Your question missed several details, so the Batch file below is just a starting point. The line number is given in the first parameter.
@echo off
setlocal EnableDelayedExpansion
call :editLine %1 < input.txt > output.txt
goto :EOF
:editLine num
set /A skipLines=%1-1
if %skipLines% gtr 0 (
rem Copy lines before the target
for /L %%i in (1,1,%skipLines%) do (
set line=
set /P line=
echo(!line!
)
)
rem Edit the target line
set line=
set /P line=
echo Line %1: "!line!"
for /F "tokens=1*" %%a in ("!line!") do (
set /P firstToken=Enter new value for "%%a":
echo !firstToken! %%b
)
rem Copy the rest of lines
:nextLine
set line=
set /P line=
if not defined line exit /B
echo !line!
goto nextLine
Previous program fails if there is an empty line after the target line: the copy process stop at that point. As I said before, this and other details can be fixed...