use strict;
use warnings;
my %list=("bob" =>123,
          "tom" => "CAT"); #Assign values
change (%list);
sub change{
    my %A = shift @_;      #Get Values
    foreach (keys %A){
        print "$_ = $A{$_}\n";
        \$A{$_} .= "hello"; #Change Values
    }
}
foreach (keys %list){
    print "$_ = $list{$_}";#Print New Values
}