diff --git a/hwe/sammo/ServerTool.php b/hwe/sammo/ServerTool.php
new file mode 100644
index 00000000..dc1cf690
--- /dev/null
+++ b/hwe/sammo/ServerTool.php
@@ -0,0 +1,79 @@
+<?php
+
+namespace sammo;
+
+final class ServerTool
+{
+    private function __construct()
+    {
+    }
+
+    public static function changeServerTerm(int $turnterm): ?string
+    {
+        // 하루에 연 단위로 게임 시간이 흘러야 함.
+        if ((120 % $turnterm) != 0) {
+            return 'invalid minute';
+        }
+
+
+        $db = DB::db();
+        $gameStor = KVStorage::getStorage($db, 'game_env');
+        $admin = $gameStor->getValues(['turntime', 'turnterm', 'year', 'startyear', 'month', 'isunited']);
+
+        $reqGameLock = $admin['isunited'] != 2;
+
+        $locked = false;
+        if($reqGameLock){
+            for ($i = 0; $i < 5; $i++) {
+                $locked = tryLock();
+                if ($locked) {
+                    break;
+                }
+                usleep(500000);
+            }
+
+            if (!$locked) {
+                return 'server busy';
+            }
+        }
+        else{
+            $locked = tryLock();
+        }
+
+        $oldunit = $admin['turnterm'] * 60;
+        $unit = $turnterm * 60;
+
+        if($unit == $oldunit){
+            if($locked){
+                unlock();
+            }
+            return null;
+        }
+
+        $unitDiff = $unit / $oldunit;
+
+        $servTurnTime = new \DateTimeImmutable($admin['turntime']);
+        foreach ($db->query('SELECT no,turntime FROM general') as $gen) {
+            $genTurnTime = new \DateTimeImmutable($gen['turntime']);
+            $timeDiff = TimeUtil::DateIntervalToSeconds($genTurnTime->diff($servTurnTime));
+            $timeDiff *= $unitDiff;
+            $newGenTurnTime = $servTurnTime->add(TimeUtil::secondsToDateInterval($timeDiff));
+
+            $db->update('general', [
+                'turntime' => $newGenTurnTime->format('Y-m-d H:i:s.u')
+            ], 'no=%i', $gen['no']);
+        }
+        $turn = ($admin['year'] - $admin['startyear']) * 12 + $admin['month'] - 1;
+        $starttime = $servTurnTime->sub(TimeUtil::secondsToDateInterval($turn * $unit))->format('Y-m-d H:i:s');
+        $starttime = cutTurn($starttime, $turnterm, false);
+        $gameStor->turnterm = $turnterm;
+        $gameStor->starttime = $starttime;
+        pushGlobalHistoryLog(["<R>★</>턴시간이 <C>{$turnterm}분</>으로 변경됩니다."]);
+
+        if($locked){
+            unlock();
+        }
+
+        return null;
+    }
+}