It's a whole lot easier and more subtle than you might expect. Perl actually passes parameters as aliases in @_ so we can:

use warnings;
use strict;

my %hash_rec = (id => "001");

doSub2($hash_rec{id2});

print "main: id2 = $hash_rec{id2}\n";


sub doSub2 {
    $_[0] = "Hello alias";
}
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Prints:

main: id2 = Hello alias
[download]

We don't usually take advantage of that trick because without due care it's likely to lead to hard to maintain code.