diff --git a/perl-xCAT/xCAT/DHCP/Backend/Kea.pm b/perl-xCAT/xCAT/DHCP/Backend/Kea.pm
index 2525ae7d3..30f6a028f 100644
--- a/perl-xCAT/xCAT/DHCP/Backend/Kea.pm
+++ b/perl-xCAT/xCAT/DHCP/Backend/Kea.pm
@@ -630,6 +630,42 @@ sub query_reservations {
     return \@found;
 }
 
+sub preserve_reservations {
+    my ( $self, $config, $intent ) = @_;
+
+    my $target_subnets = $intent->{subnets} || [];
+    return $intent unless @$target_subnets;
+
+    my $target_config = $config->{Dhcp6}
+      ? { Dhcp6 => { subnet6 => $target_subnets } }
+      : { Dhcp4 => { subnet4 => $target_subnets } };
+
+    foreach my $source_subnet ( _subnets_for_config($config) ) {
+        foreach my $reservation ( @{ $source_subnet->{reservations} || [] } ) {
+            my $ip = $reservation->{'ip-address'};
+            $ip = $reservation->{'ip-addresses'}[0]
+              if !$ip && ref( $reservation->{'ip-addresses'} ) eq 'ARRAY';
+
+            my $target_subnet;
+            if ($ip) {
+                my $subnet_id = $self->subnet_id_for_ip( $target_config, $ip );
+                $target_subnet = _find_subnet_by_id( $target_config, $subnet_id ) if defined($subnet_id);
+            }
+            if ( !$target_subnet && $source_subnet->{subnet} ) {
+                ($target_subnet) = grep {
+                    ( $_->{subnet} || '' ) eq $source_subnet->{subnet}
+                } @$target_subnets;
+            }
+            next unless $target_subnet;
+
+            $target_subnet->{reservations} ||= [];
+            push @{ $target_subnet->{reservations} }, { %$reservation };
+        }
+    }
+
+    return $intent;
+}
+
 sub subnet_id_for_ip {
     my ( $self, $config, $ip ) = @_;
 
diff --git a/xCAT-server/lib/xcat/plugins/dhcp.pm b/xCAT-server/lib/xcat/plugins/dhcp.pm
index 1a0e5ba42..396370d9a 100644
--- a/xCAT-server/lib/xcat/plugins/dhcp.pm
+++ b/xCAT-server/lib/xcat/plugins/dhcp.pm
@@ -2380,6 +2380,24 @@ sub kea_process_request
     }
 
     if ($opt->{n}) {
+        my $loaded4 = $backend->load_dhcp4_config();
+        if ($loaded4->{error}) {
+            $callback->({ error => [ $loaded4->{error} ], errorcode => [1] });
+            flock($dhcplockfd, LOCK_UN);
+            return;
+        }
+        $backend->preserve_reservations($loaded4, $intent4);
+
+        if ($using_dhcp6) {
+            my $loaded6 = $backend->load_dhcp6_config();
+            if ($loaded6->{error}) {
+                $callback->({ error => [ $loaded6->{error} ], errorcode => [1] });
+                flock($dhcplockfd, LOCK_UN);
+                return;
+            }
+            $backend->preserve_reservations($loaded6, $intent6);
+        }
+
         my $result = $backend->write_dhcp4_config($intent4, backup_existing => 1);
         if ($result->{error}) {
             $callback->({ error => [ $result->{error} ], errorcode => [1] });
diff --git a/xCAT-test/unit/dhcp_kea_renderer.t b/xCAT-test/unit/dhcp_kea_renderer.t
index 89ae04cfb..877877090 100644
--- a/xCAT-test/unit/dhcp_kea_renderer.t
+++ b/xCAT-test/unit/dhcp_kea_renderer.t
@@ -329,6 +329,96 @@ my $deleted = $backend->delete_reservations( $reservation_config, { 'hw-address'
 is( scalar @$deleted, 1, 'reservation delete returns deleted reservation' );
 is( scalar @{ $reservation_config->{Dhcp4}{subnet4}[0]{reservations} }, 0, 'reservation is removed from config' );
 
+my $existing_dhcp4 = {
+    Dhcp4 => {
+        subnet4 => [
+            {
+                id           => 1,
+                subnet       => '10.20.0.0/24',
+                reservations => [
+                    {
+                        'hw-address' => '00:11:22:33:44:66',
+                        'ip-address' => '10.20.0.12',
+                        hostname     => 'node20',
+                    },
+                ],
+            },
+            {
+                id           => 2,
+                subnet       => '10.30.0.0/24',
+                reservations => [
+                    {
+                        'hw-address' => '00:11:22:33:44:77',
+                        'ip-address' => '10.30.0.12',
+                        hostname     => 'removed-node',
+                    },
+                ],
+            },
+        ],
+    },
+};
+my $regenerated_dhcp4 = {
+    subnets => [
+        {
+            id     => 9,
+            subnet => '10.20.0.0/24',
+        },
+    ],
+};
+$backend->preserve_reservations( $existing_dhcp4, $regenerated_dhcp4 );
+is_deeply(
+    $regenerated_dhcp4->{subnets}[0]{reservations},
+    $existing_dhcp4->{Dhcp4}{subnet4}[0]{reservations},
+    'regeneration preserves IPv4 reservations in the matching subnet'
+);
+is(
+    scalar @{ $regenerated_dhcp4->{subnets}[0]{reservations} },
+    1,
+    'regeneration drops reservations for removed IPv4 subnets'
+);
+is(
+    $regenerated_dhcp4->{subnets}[0]{id},
+    9,
+    'regeneration does not copy the old IPv4 subnet id'
+);
+
+my $existing_dhcp6 = {
+    Dhcp6 => {
+        subnet6 => [
+            {
+                id           => 10001,
+                subnet       => '2001:db8:20::/64',
+                reservations => [
+                    {
+                        duid           => '00:04:00:11:22:33:44:55:66:77:88:99:aa:bb:cc:dd:ee:ff',
+                        'ip-addresses' => ['2001:db8:20::12'],
+                        hostname       => 'node20-v6',
+                    },
+                ],
+            },
+        ],
+    },
+};
+my $regenerated_dhcp6 = {
+    subnets => [
+        {
+            id     => 10009,
+            subnet => '2001:db8:20::/64',
+        },
+    ],
+};
+$backend->preserve_reservations( $existing_dhcp6, $regenerated_dhcp6 );
+is_deeply(
+    $regenerated_dhcp6->{subnets}[0]{reservations},
+    $existing_dhcp6->{Dhcp6}{subnet6}[0]{reservations},
+    'regeneration preserves IPv6 reservations in the matching subnet'
+);
+is(
+    $regenerated_dhcp6->{subnets}[0]{id},
+    10009,
+    'regeneration does not copy the old IPv6 subnet id'
+);
+
 my $hookdir = tempdir(CLEANUP => 1);
 my $hook = "$hookdir/libdhcp_host_cmds.so";
 open(my $hookfh, '>', $hook) or die "Unable to create fake hook: $!";