how to replace the special character with another using SED

I have the replace the pattern in the file , ); to );
Could someone please help me to get this command.

you means this:

echo "a,);b" |sed 's/,);/);/'
a);b
or:
echo "a,);b" |sed 's/,//'
a);b

Please post sample before and after lines. Please post in "code tags" so we can see any space characters.