#!/usr/bin/env perl

use strict;
use warnings;
use Data::Dumper;

my $x = { a => [ 1, 2 ], c => [ qw( a b c ) ], d => 100 };
print 'original: ', Dumper $x;

# one by one replacement: c -> b, d -> c
$x->{b} = delete $x->{c};
$x->{c} = delete $x->{d};
print 'modified: ', Dumper $x;

# in one run replacement: b, c -> c, d
@$x{qw( c d )} = delete @$x{qw( b c )};
print 'reverted: ', Dumper $x;