Code:
$
$ cat csv.txt
"104787","MILLER,BOB M.","","Automatic refund. Expected over-payment","67.47","A","225","","128110048","1/8/2011 15:14:20"
"104196","REBECCA M MANNERS","","Automatic refund. Expected over-payment","53.21","A","225","","128110047","12/28/2011 15:14:20"
"104415","LEMMING,LETTUCE","","Automatic refund. Expected over-payment","257.03","A","225","","128110046","7/22/2011 15:14:20"
"104535","BUYTRON, LATOYA","","Automatic refund. Expected over-payment","281.51","A","225","","128110045","10/13/2011 15:14:20"
"104698","Jesus Rodriguez","Chase Bank","Prorate for december. 512-784-2711","200.00","N","225","","128110049","12/25/2011 15:14:20"
$
$
$ perl -ne 'chomp;
m|^(.*)\b(\d+)/(\d+)/(\d+)\b(.*)$|;
printf ("%s%04d-%02d-%02d%s\n", $1,$4,$3,$2,$5)
' csv.txt
"104787","MILLER,BOB M.","","Automatic refund. Expected over-payment","67.47","A","225","","128110048","2011-08-01 15:14:20"
"104196","REBECCA M MANNERS","","Automatic refund. Expected over-payment","53.21","A","225","","128110047","2011-28-12 15:14:20"
"104415","LEMMING,LETTUCE","","Automatic refund. Expected over-payment","257.03","A","225","","128110046","2011-22-07 15:14:20"
"104535","BUYTRON, LATOYA","","Automatic refund. Expected over-payment","281.51","A","225","","128110045","2011-13-10 15:14:20"
"104698","Jesus Rodriguez","Chase Bank","Prorate for december. 512-784-2711","200.00","N","225","","128110049","2011-25-12 15:14:20"
$
$