diff --git a/Api.SeaHavenIndustries/Controllers/WorkOrderController.cs b/Api.SeaHavenIndustries/Controllers/WorkOrderController.cs
index 9c73034..82795a3 100644
--- a/Api.SeaHavenIndustries/Controllers/WorkOrderController.cs
+++ b/Api.SeaHavenIndustries/Controllers/WorkOrderController.cs
@@ -100,6 +100,7 @@ namespace Api.SeaHavenIndustries.Controllers
                     LocationId = model.LocationId,
                     AssignTo = model.AssignTo,
                     DueDate = model.DueDate,
+                    ScheduledDate = model.ScheduledDate,
                     CompletedDate = model.CompletedDate,
                     ContactIds = model.ContactIds,
                     CategoryIds = model.CategoryIds,
diff --git a/SeaHaven.Services/DTOs/WorkOrderDTOs.cs b/SeaHaven.Services/DTOs/WorkOrderDTOs.cs
index f4f6003..fab9492 100644
--- a/SeaHaven.Services/DTOs/WorkOrderDTOs.cs
+++ b/SeaHaven.Services/DTOs/WorkOrderDTOs.cs
@@ -111,6 +111,7 @@ namespace SeaHaven.Services.DTOs
         public int? LocationId { get; set; }
         public string? AssignTo { get; set; }
         public DateTime? DueDate { get; set; }
+        public DateTime? ScheduledDate { get; set; }
         public DateTime? CompletedDate { get; set; }
 
         public static void UpdateEntity(UpdateWorkOrderDTO dto, WorkOrder entity)
@@ -124,6 +125,7 @@ namespace SeaHaven.Services.DTOs
             if (dto.LocationId.HasValue) entity.LocationId = dto.LocationId;
             if (dto.AssignTo != null) entity.AssignTo = dto.AssignTo;
             if (dto.DueDate.HasValue) entity.DueDate = dto.DueDate;
+            if (dto.ScheduledDate.HasValue) entity.ScheduledDate = dto.ScheduledDate.Value.Date;
             if (dto.CompletedDate.HasValue) entity.CompletedDate = dto.CompletedDate;
 
             entity.LastModificationTime = DateTime.UtcNow;
diff --git a/SeaHaven.Services/DTOs/WorkOrderServiceDTOs.cs b/SeaHaven.Services/DTOs/WorkOrderServiceDTOs.cs
index 7665da4..fb59789 100644
--- a/SeaHaven.Services/DTOs/WorkOrderServiceDTOs.cs
+++ b/SeaHaven.Services/DTOs/WorkOrderServiceDTOs.cs
@@ -32,6 +32,7 @@ namespace SeaHaven.Services.DTOs
         public int? LocationId { get; set; }
         public string? AssignTo { get; set; }
         public DateTime? DueDate { get; set; }
+        public DateTime? ScheduledDate { get; set; }
         public DateTime? CompletedDate { get; set; }
         public List<int>? ContactIds { get; set; }
         public List<int>? CategoryIds { get; set; }
diff --git a/SeaHaven.Services/Implementation/WorkOrderService.cs b/SeaHaven.Services/Implementation/WorkOrderService.cs
index 6cfa57f..19695b2 100644
--- a/SeaHaven.Services/Implementation/WorkOrderService.cs
+++ b/SeaHaven.Services/Implementation/WorkOrderService.cs
@@ -6,6 +6,7 @@ using SeaHaven.DataServices.Interfaces;
 using SeaHaven.DataServices.Models;
 using SeaHaven.Services.DTOs;
 using SeaHaven.Services.Exceptions;
+using SeaHaven.Services.Helpers;
 using SeaHaven.Services.Interfaces;
 using SeaHaven.Services.Validation;
 
@@ -105,7 +106,19 @@ namespace SeaHaven.Services.Implementation
             var changes = new List<string>();
             changes.AddRange(TrackChanges(existingWorkOrder, dto));
 
+            var scheduledDateChanged = dto.ScheduledDate.HasValue
+                && dto.ScheduledDate.Value.Date != existingWorkOrder.ScheduledDate?.Date;
+            var previousIsAddOn = existingWorkOrder.IsAddOn;
             UpdateWorkOrderDTO.UpdateEntity(dto, existingWorkOrder);
+            if (scheduledDateChanged)
+            {
+                existingWorkOrder.IsAddOn = WorkOrderAddonCutoff.RecalculateIsAddOnFromSchedule(
+                    existingWorkOrder.CreatedDate ?? DateTime.UtcNow,
+                    existingWorkOrder.ScheduledDate,
+                    existingWorkOrder.TargetWeek);
+                if (existingWorkOrder.IsAddOn != previousIsAddOn)
+                    changes.Add($"IsAddOn: {previousIsAddOn} → {existingWorkOrder.IsAddOn}");
+            }
             await _workOrderDataService.UpdateAsync(existingWorkOrder);
 
             if (changes.Any())
@@ -405,6 +418,7 @@ namespace SeaHaven.Services.Implementation
                 LocationId = input.LocationId,
                 AssignTo = input.AssignTo,
                 DueDate = input.DueDate,
+                ScheduledDate = input.ScheduledDate,
                 CompletedDate = input.CompletedDate
             };
 
@@ -630,6 +644,8 @@ namespace SeaHaven.Services.Implementation
                 changes.Add($"Assigned To: {existing.AssignTo} → {dto.AssignTo}");
             if (dto.DueDate.HasValue && dto.DueDate != existing.DueDate)
                 changes.Add($"Due Date: {existing.DueDate:yyyy-MM-dd} → {dto.DueDate:yyyy-MM-dd}");
+            if (dto.ScheduledDate.HasValue && dto.ScheduledDate.Value.Date != existing.ScheduledDate?.Date)
+                changes.Add($"Schedule On: {existing.ScheduledDate:yyyy-MM-dd} → {dto.ScheduledDate:yyyy-MM-dd}");
             return changes;
         }
 
diff --git a/SeaHavenIndustries.Tests/WorkOrderEditAddonRescheduleTests.cs b/SeaHavenIndustries.Tests/WorkOrderEditAddonRescheduleTests.cs
new file mode 100644
index 0000000..e595ea7
--- /dev/null
+++ b/SeaHavenIndustries.Tests/WorkOrderEditAddonRescheduleTests.cs
@@ -0,0 +1,78 @@
+using System.Security.Claims;
+using Api.SeaHavenIndustries.Controllers;
+using Api.SeaHavenIndustries.DTOs;
+using Data.SeaHavenIndustries;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging.Abstractions;
+using SeaHaven.DataServices.Implementation;
+using SeaHaven.DataServices.Models;
+using SeaHaven.Services.Implementation;
+using SeaHaven.Services.Validation;
+
+namespace SeaHavenIndustries.Tests;
+
+public sealed class WorkOrderEditAddonRescheduleTests
+{
+    [Fact]
+    public async Task EditWorkorder_RescheduleIntoEarlierWeek_EnablesAndAuditsAddOn()
+    {
+        var options = new DbContextOptionsBuilder<ApplicationDbContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .Options;
+        await using var context = new ApplicationDbContext(options);
+        var workOrder = new WorkOrder
+        {
+            Id = 1,
+            CreatedDate = new DateTime(2026, 6, 21, 0, 0, 0, DateTimeKind.Utc),
+            ScheduledDate = new DateTime(2026, 6, 29),
+            IsAddOn = false
+        };
+        context.workOrders.Add(workOrder);
+        await context.SaveChangesAsync();
+
+        var accountResolver = WorkOrderAccountTestHelpers.Resolver(context);
+        var workOrderService = new WorkOrderService(
+            new WorkOrderDataService(context),
+            new CommentDataService(context),
+            new UserDataService(context),
+            new QuotesDataService(context),
+            fileStorage: null!,
+            new CreateWorkOrderValidation(),
+            new UpdateWorkOrderValidation(),
+            accountResolver);
+        var controller = new WorkOrderController(
+            workOrderService,
+            accountResolver,
+            NullLogger<WorkOrderController>.Instance)
+        {
+            ControllerContext = new ControllerContext
+            {
+                HttpContext = new DefaultHttpContext
+                {
+                    User = new ClaimsPrincipal(new ClaimsIdentity(
+                        new[] { new Claim(ClaimTypes.NameIdentifier, "dispatcher-1") },
+                        authenticationType: "test"))
+                }
+            }
+        };
+
+        var result = await controller.Editworkorder(new EditWorkorder_DTO
+        {
+            Id = 1,
+            ScheduledDate = new DateTime(2026, 6, 25)
+        });
+
+        Assert.IsType<OkObjectResult>(result);
+        var persisted = await context.workOrders.SingleAsync(x => x.Id == 1);
+        Assert.Equal(new DateTime(2026, 6, 25), persisted.ScheduledDate);
+        Assert.True(persisted.IsAddOn);
+        var audit = await context.WorkOrderAuditLogs
+            .Where(x => x.WorkOrderId == 1)
+            .ToListAsync();
+        Assert.Single(audit);
+        Assert.Contains(audit, x => x.FieldName?.Contains("Schedule On", StringComparison.Ordinal) == true);
+        Assert.Contains(audit, x => x.FieldName?.Contains("IsAddOn", StringComparison.Ordinal) == true);
+    }
+}