diff --git a/javaTest/src/main/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManager.java b/javaTest/src/main/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManager.java
index e7a8be3..b55ca1f 100644
--- a/javaTest/src/main/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManager.java
+++ b/javaTest/src/main/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManager.java
@@ -56,6 +56,98 @@ public final class CorridorReservationManager {
         return ReservationDecision.granted();
     }
 
+    /**
+     * 原子替换一个活动任务尚未通过的走廊方向预约。
+     *
+     * <p>方法先把当前任务自己的旧预约视为可替换资源，对新路线做完整预检；任一新边与其他任务方向冲突时
+     * 直接拒绝，旧预约保持原样。只有全部新边通过后才在同一次调用中提交移除和新增，因此重规划不会形成
+     * “旧路线已释放、新路线尚未取得”的安全空窗。
+     *
+     * @param taskId 正在重规划的任务
+     * @param newRoute 从车辆当前位置开始的新剩余路线
+     * @param effectivePriority 当前饥饿保护后的有效优先级
+     * @param arrivalMillis 任务到达队列的仿真时间
+     * @return 替换是否成功以及失败时优先持有冲突方向的任务
+     */
+    public ReservationDecision replaceRoute(String taskId, List<String> newRoute,
+                                            int effectivePriority, long arrivalMillis) {
+        if (taskId == null || taskId.trim().isEmpty()
+                || newRoute == null || newRoute.isEmpty()) {
+            throw new IllegalArgumentException("task id and new route are required");
+        }
+
+        List<EdgeRequest> requests = new ArrayList<EdgeRequest>();
+        for (int i = 1; i < newRoute.size(); i++) {
+            EdgeRequest request = request(newRoute.get(i - 1), newRoute.get(i));
+            requests.add(request);
+            EdgeReservation existing = edges.get(request.edgeId);
+            if (existing == null || existing.direction == request.direction) continue;
+
+            // 当前任务旧预约可以被翻转；其他任务仍持有旧方向时，新路线不能提交。
+            Set<String> otherHolders = new LinkedHashSet<String>(existing.holders);
+            otherHolders.remove(taskId);
+            if (!otherHolders.isEmpty()) {
+                return ReservationDecision.denied(bestOwner(otherHolders),
+                        "CORRIDOR_DIRECTION_OWNED");
+            }
+        }
+
+        // 预检全部通过后才开始提交。先移除当前任务，绝不触碰同向共享该边的其他任务。
+        Set<String> oldEdges = taskEdges.get(taskId);
+        if (oldEdges != null) {
+            for (String edgeId : new ArrayList<String>(oldEdges)) {
+                EdgeReservation reservation = edges.get(edgeId);
+                if (reservation == null) continue;
+                reservation.holders.remove(taskId);
+                if (reservation.holders.isEmpty()) edges.remove(edgeId);
+            }
+        }
+
+        Rank rank = new Rank(taskId, effectivePriority, arrivalMillis);
+        ranks.put(taskId, rank);
+        Set<String> replacementEdges = new LinkedHashSet<String>();
+        for (EdgeRequest request : requests) {
+            EdgeReservation reservation = edges.get(request.edgeId);
+            if (reservation == null) {
+                reservation = new EdgeReservation(request.direction);
+                edges.put(request.edgeId, reservation);
+            }
+            reservation.holders.add(taskId);
+            replacementEdges.add(request.edgeId);
+        }
+        if (replacementEdges.isEmpty()) {
+            taskEdges.remove(taskId);
+        } else {
+            taskEdges.put(taskId, replacementEdges);
+        }
+        return ReservationDecision.granted();
+    }
+
+    /**
+     * 冻结当前全部走廊方向和持有任务，供路线质量评价和审计报告使用。
+     *
+     * @return 按物理边规范键排序的不可变预约列表
+     */
+    public List<CorridorReservationSnapshot> snapshot() {
+        List<String> edgeIds = new ArrayList<String>(edges.keySet());
+        Collections.sort(edgeIds);
+        List<CorridorReservationSnapshot> result =
+                new ArrayList<CorridorReservationSnapshot>();
+        for (String edgeId : edgeIds) {
+            EdgeReservation reservation = edges.get(edgeId);
+            int separator = edgeId.indexOf('|');
+            String left = edgeId.substring(0, separator);
+            String right = edgeId.substring(separator + 1);
+            List<String> holders = new ArrayList<String>(reservation.holders);
+            Collections.sort(holders);
+            result.add(new CorridorReservationSnapshot(
+                    reservation.direction > 0 ? left : right,
+                    reservation.direction > 0 ? right : left,
+                    holders));
+        }
+        return Collections.unmodifiableList(result);
+    }
+
     /**
      * 在车辆通过一条边后立即释放该段走廊，允许后续同向或反向任务重新竞争资源。
      * @param taskId 执行该处理所需的 task id 输入。
@@ -207,6 +299,29 @@ public final class CorridorReservationManager {
         public String getReason() { return reason; }
     }
 
+    /** 一条物理走廊当前的有向预约及全部合法同向持有者。 */
+    public static final class CorridorReservationSnapshot {
+        private final String fromSite;
+        private final String toSite;
+        private final List<String> taskIds;
+
+        private CorridorReservationSnapshot(String fromSite, String toSite,
+                                            List<String> taskIds) {
+            this.fromSite = fromSite;
+            this.toSite = toSite;
+            this.taskIds = Collections.unmodifiableList(new ArrayList<String>(taskIds));
+        }
+
+        /** 返回预约方向的起点。 */
+        public String getFromSite() { return fromSite; }
+
+        /** 返回预约方向的终点。 */
+        public String getToSite() { return toSite; }
+
+        /** 返回共享该方向预约的任务编号，按编号稳定排序。 */
+        public List<String> getTaskIds() { return taskIds; }
+    }
+
     private static final class EdgeReservation {
         private final int direction;
         private final Set<String> holders = new LinkedHashSet<String>();
diff --git a/javaTest/src/test/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManagerTest.java b/javaTest/src/test/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManagerTest.java
index 0f11da9..6f3075f 100644
--- a/javaTest/src/test/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManagerTest.java
+++ b/javaTest/src/test/java/com/ft546/wcs/shadow/history/simulation/CorridorReservationManagerTest.java
@@ -3,6 +3,8 @@ package com.ft546.wcs.shadow.history.simulation;
 import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
+import java.util.LinkedHashSet;
+import java.util.Set;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
@@ -50,4 +52,53 @@ class CorridorReservationManagerTest {
                 .isGranted());
         assertEquals("FIRST", manager.ownerFor("A", "B"));
     }
+
+    @Test
+    void rejectedReplacementKeepsEveryOldReservation() {
+        CorridorReservationManager manager = new CorridorReservationManager();
+        assertTrue(manager.reserve("TASK-1", Arrays.asList("A", "B", "C"), 1, 10L)
+                .isGranted());
+        assertTrue(manager.reserve("TASK-2", Arrays.asList("C", "D"), 2, 20L)
+                .isGranted());
+
+        CorridorReservationManager.ReservationDecision denied = manager.replaceRoute(
+                "TASK-1", Arrays.asList("A", "D", "C"), 1, 10L);
+
+        assertFalse(denied.isGranted());
+        assertEquals(new LinkedHashSet<String>(Arrays.asList("A->B", "B->C")),
+                edgesFor(manager, "TASK-1"));
+        assertEquals("TASK-1", manager.ownerFor("A", "B"));
+        assertEquals("TASK-1", manager.ownerFor("B", "C"));
+    }
+
+    @Test
+    void successfulReplacementCommitsNewRouteAndPreservesSharedOldHolder() {
+        CorridorReservationManager manager = new CorridorReservationManager();
+        assertTrue(manager.reserve("TASK-1", Arrays.asList("A", "B", "C"), 1, 10L)
+                .isGranted());
+        assertTrue(manager.reserve("TASK-2", Arrays.asList("A", "B", "C"), 2, 20L)
+                .isGranted());
+
+        CorridorReservationManager.ReservationDecision replaced = manager.replaceRoute(
+                "TASK-1", Arrays.asList("A", "D", "C"), 1, 10L);
+
+        assertTrue(replaced.isGranted());
+        assertEquals(new LinkedHashSet<String>(Arrays.asList("A->D", "D->C")),
+                edgesFor(manager, "TASK-1"));
+        assertEquals(new LinkedHashSet<String>(Arrays.asList("A->B", "B->C")),
+                edgesFor(manager, "TASK-2"));
+        assertEquals("TASK-2", manager.ownerFor("A", "B"));
+        assertEquals("TASK-1", manager.ownerFor("A", "D"));
+    }
+
+    private Set<String> edgesFor(CorridorReservationManager manager, String taskId) {
+        Set<String> edges = new LinkedHashSet<String>();
+        for (CorridorReservationManager.CorridorReservationSnapshot reservation
+                : manager.snapshot()) {
+            if (reservation.getTaskIds().contains(taskId)) {
+                edges.add(reservation.getFromSite() + "->" + reservation.getToSite());
+            }
+        }
+        return edges;
+    }
 }