This worked for me:
echo '"prabhat,kumar",19,2000,"bangalore,India"' | awk -F, '{print $1,$2,$3,$4,$5,$6}'|awk -F\" '{print $2,$3,$4}'|awk -F\ '{print $1","$2,$3,$4,$5","$6}'
$ echo '"prabhat,kumar",19,2000,"bangalore,India"' |
awk -F, '{print $1,$2,$3,$4,$5,$6}'|
awk -F\" '{print $2,$3,$4}'|awk -F\ '{print $1","$2,$3,$4,$5","$6}'`