For arbitrary depth structure you could use (untested)

use Data::Visitor::Callback;
my $v = Data::Visitor::Callback->new(
    ignore_return_values => 1,
    hash => sub {
        my %map = ( qw/ abeLincoln lincoln / );
        my $ref = $_; ##!!!
        my %new ;
        for my $key ( %{$ref} ){
            my $fkey = $map{$_} ;
            $new{ defined $fkey ? $fkey : $key } = $ref->{$key};
        }
        %{$ref} = %new;
    },
);
$v->visit();
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