#!/usr/bin/env perl

use strict;
use warnings;

my %months;
@months{qw{Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec}}
    = '01' .. '12';
my $out_fmt = '%4d-%s-%02d';

my ($Map_Request_Date,
    $Map_Due_Date,
    $Map_Cutover_Date,
    $Map_Complete_Date,
    $Map_Approved_Date
) = (
    'Jan  1 2017 12:00',
    'Jan 31 2017 12:00',
    'Feb 28 2017 23:59',
    'Mar  1 2017 12:01',
    'Dec 31 1999 0:01'
);

my @var_refs = \(
    $Map_Request_Date,
    $Map_Due_Date,
    $Map_Cutover_Date,
    $Map_Complete_Date,
    $Map_Approved_Date
);

print "$$_\n" for @var_refs;

for (@var_refs) {
    my ($m, $d, $y, undef) = split ' ', $$_;
    $$_ = sprintf $out_fmt, $y, $months{$m}, $d;
}

print "$$_\n" for @var_refs;

##</code><code>##

Jan  1 2017 12:00
Jan 31 2017 12:00
Feb 28 2017 23:59
Mar  1 2017 12:01
Dec 31 1999 0:01
2017-01-01
2017-01-31
2017-02-28
2017-03-01
1999-12-31