The following code uses Date::Manip to parse a time and adjust it from AKST (Alaska Standard) to EST:

use strict;
use warnings;
use Date::Manip;

Date_Init ("TZ=PST"); # May not be needed and timezone irrelevant
my $now = Date_ConvTZ (ParseDate ('00:00:00'), 'AKST', 'EST');

print UnixDate ($now, '%H:%M:%S');
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Prints:

04:00:00
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