Hi Corion, well first I found a few mistakes I made, but my lines are wrapping and not breaking into new lines for each account. Corrected code below but not working as expected.

use strict;
use warnings;

my %reformat;
my $re = qr{^(H\d+,\d+,)(.*)$};


    open (NEW, ">", "Notes_Test_OUTPUT.txt" ) or die "could not open:$
+!";
    open (FILE, "<", "Notes_Test.txt") or die "could not open:$!";

    while (<FILE>) {
            chomp;
            /$re/;
                push @{ $reformat{$1} }, $2; 
        print NEW $_, join ' ', @{ $reformat{$_} } for keys %reformat;
}
close (FILE);
close (NEW);
[download]

In what way is it not working as expected?

Maybe you can show some relevant input and relevant output and explain how the output differs from what you expect?

Also, I notice that your indentation is very inconsistent. Consider applying a consistent way of indenting. For example, indent the complete loop body by four spaces below the while but don't indent anything else, as the while(...) { ... } statement is the only block within your program.

While indenting, you might find that some things are within the block of your loop which you did not want there.