use warnings;
use strict;
use JSON;

my $original = '{"OWNER":"KeyProjects","age1":"eon","ht1":"moo"}';
my $desired  = '{"OWNER":"KeyProjects","scheduled":{"age1":"eon","ht1":"moo"}}';

my $data = decode_json($original);
print "The owner is; ", $data->{OWNER}, $/;
print "age1 is: ", $data->{age1}, $/;
my $age = delete $data->{age1};
print "age1 is now: ", $data->{age1}, $/; # Empty, we deleted it...
# ...while putting it into-
print "Here I am: $age\n"; # \n = $/, usually/sort-of.
my $ht = delete $data->{ht1};

my %sub_hash = ( ht1 => $ht, age1 => $age );
# Perl auto-vivivies data-
$data->{scheduled} = \%sub_hash; # \% is like {}

print encode_json( $data ), $/;
# {"scheduled":{"age1":"eon","ht1":"moo"},"OWNER":"KeyProjects"}
# Remember, order is irrelevant in Objects.