diff --git a/src/app/(protected)/workorders/_components/detail/tabs/slide-over-info-tab-edit-view.tsx b/src/app/(protected)/workorders/_components/detail/tabs/slide-over-info-tab-edit-view.tsx
index da8b4264..2a6afbb3 100644
--- a/src/app/(protected)/workorders/_components/detail/tabs/slide-over-info-tab-edit-view.tsx
+++ b/src/app/(protected)/workorders/_components/detail/tabs/slide-over-info-tab-edit-view.tsx
@@ -17,7 +17,7 @@ import type {
 import type { WorkOrderTableRow } from "@/domain/work-orders/types/work-order-table-row";
 import type { WizardWOStatus } from "@/domain/work-orders/types/work-order-wizard";
 import type { Service } from "@/domain/services/types/service";
-import { isServiceEligibleForWorkOrderType } from "@/domain/services/utils/services-for-work-order-type";
+import { serviceSupportsWorkOrderType } from "@/domain/services/utils/services-for-work-order-type";
 import { serviceIdentityPatch } from "@/domain/work-orders/utils/service-identity-patch";
 import { deriveDayFields } from "@/domain/work-orders/utils/table-day-utils";
 import { toVendorTablePatch } from "@/domain/work-orders/utils/vendor-assignment-patch";
@@ -180,7 +180,7 @@ export function SlideOverInfoTabEditView({
             onDraftChange(
               draft.serviceId != null &&
                 selectedService != null &&
-                !isServiceEligibleForWorkOrderType(selectedService, type)
+                !serviceSupportsWorkOrderType(selectedService, type)
                 ? { type, severity, serviceId: null, pm: "" }
                 : { type, severity },
             );
diff --git a/src/app/(protected)/workorders/_components/list/table/save-existing-row-type.ts b/src/app/(protected)/workorders/_components/list/table/save-existing-row-type.ts
index bc32d6df..6e5e0bf7 100644
--- a/src/app/(protected)/workorders/_components/list/table/save-existing-row-type.ts
+++ b/src/app/(protected)/workorders/_components/list/table/save-existing-row-type.ts
@@ -6,7 +6,7 @@ import type {
 } from "@/domain/work-orders/types/work-order-table-row";
 import type { WOType } from "@/domain/work-orders/types/work-order-wizard";
 import type { Service } from "@/domain/services/types/service";
-import { isServiceEligibleForWorkOrderType } from "@/domain/services/utils/services-for-work-order-type";
+import { serviceSupportsWorkOrderType } from "@/domain/services/utils/services-for-work-order-type";
 import {
   formatSeverityEscalationToast,
   shouldAnnounceSeverityEscalation,
@@ -31,7 +31,7 @@ export function saveExistingRowType(
   const clearService =
     row.serviceId != null &&
     selectedService != null &&
-    !isServiceEligibleForWorkOrderType(selectedService, type);
+    !serviceSupportsWorkOrderType(selectedService, type);
   const patch = clearService ? { type, severity, serviceId: null, pm: "" } : { type, severity };
   if (!shouldAnnounceSeverityEscalation(row.severity, severity)) {
     onPatch(row.id, patch);
diff --git a/src/domain/services/utils/services-for-work-order-type.ts b/src/domain/services/utils/services-for-work-order-type.ts
index c11641cf..6ba6096a 100644
--- a/src/domain/services/utils/services-for-work-order-type.ts
+++ b/src/domain/services/utils/services-for-work-order-type.ts
@@ -10,5 +10,10 @@ export function servicesForWorkOrderType(services: Service[], type: WOType | "")
 }
 
 export function isServiceEligibleForWorkOrderType(service: Service, type: WOType | ""): boolean {
-  return service.isActive && service.supportedWorkOrderTypes.includes(serviceWorkOrderType(type));
+  return service.isActive && serviceSupportsWorkOrderType(service, type);
+}
+
+/** Whether a service definition supports a WO type, regardless of active assignment status. */
+export function serviceSupportsWorkOrderType(service: Service, type: WOType | ""): boolean {
+  return service.supportedWorkOrderTypes.includes(serviceWorkOrderType(type));
 }
diff --git a/src/test/app/(protected)/workorders/save-existing-row-type.test.ts b/src/test/app/(protected)/workorders/save-existing-row-type.test.ts
index 7754c9cf..11809966 100644
--- a/src/test/app/(protected)/workorders/save-existing-row-type.test.ts
+++ b/src/test/app/(protected)/workorders/save-existing-row-type.test.ts
@@ -78,16 +78,36 @@ describe("saveExistingRowType", () => {
       },
     ];
 
-    saveExistingRowType(onPatch, { ...row, serviceId: 701 }, "Reactive", null, services);
+    saveExistingRowType(onPatch, { ...row, serviceId: 701 }, "Emergency", null, services);
 
     expect(onPatch).toHaveBeenCalledWith(7, {
-      type: "Reactive",
+      type: "Emergency",
       severity: null,
       serviceId: null,
       pm: "",
     });
   });
 
+  it("preserves a known inactive historical service that supports the new type", () => {
+    const onPatch = vi.fn();
+    const services: Service[] = [
+      {
+        id: 702,
+        name: "Retired Multi-type Service",
+        trade: "Electrical",
+        iconKey: "wrench",
+        requiresCompletionDocument: false,
+        completionDocTemplate: null,
+        isActive: false,
+        supportedWorkOrderTypes: ["PM", "Reactive"],
+      },
+    ];
+
+    saveExistingRowType(onPatch, { ...row, serviceId: 702 }, "Reactive", null, services);
+
+    expect(onPatch).toHaveBeenCalledWith(7, { type: "Reactive", severity: null });
+  });
+
   it("clears a known inactive historical service before type change", () => {
     const onPatch = vi.fn();
     const services: Service[] = [
@@ -103,10 +123,10 @@ describe("saveExistingRowType", () => {
       },
     ];
 
-    saveExistingRowType(onPatch, { ...row, serviceId: 701 }, "Reactive", null, services);
+    saveExistingRowType(onPatch, { ...row, serviceId: 701 }, "Emergency", null, services);
 
     expect(onPatch).toHaveBeenCalledWith(7, {
-      type: "Reactive",
+      type: "Emergency",
       severity: null,
       serviceId: null,
       pm: "",
diff --git a/src/test/app/(protected)/workorders/slide-over-info-tab-edit-view-additional-contacts.test.tsx b/src/test/app/(protected)/workorders/slide-over-info-tab-edit-view-additional-contacts.test.tsx
index 19b7be33..8457d0ac 100644
--- a/src/test/app/(protected)/workorders/slide-over-info-tab-edit-view-additional-contacts.test.tsx
+++ b/src/test/app/(protected)/workorders/slide-over-info-tab-edit-view-additional-contacts.test.tsx
@@ -50,10 +50,19 @@ vi.mock(
   }),
 );
 vi.mock("@/app/(protected)/workorders/_components/list/table/cells/type-cell", () => ({
-  TypeCell: ({ onSave }: { onSave: (type: "Reactive", severity: number) => void }) => (
-    <button type="button" onClick={() => onSave("Reactive", 2)}>
-      Change type to Reactive
-    </button>
+  TypeCell: ({
+    onSave,
+  }: {
+    onSave: (type: "Reactive" | "Emergency", severity: number) => void;
+  }) => (
+    <>
+      <button type="button" onClick={() => onSave("Reactive", 2)}>
+        Change type to Reactive
+      </button>
+      <button type="button" onClick={() => onSave("Emergency", 2)}>
+        Change type to Emergency
+      </button>
+    </>
   ),
 }));
 vi.mock("@/app/(protected)/workorders/_components/list/table/cells/assigned-to-cell", () => ({
@@ -227,12 +236,63 @@ describe("SlideOverInfoTabEditView additional contacts", () => {
     }
 
     renderWithProviders(<SlideOverSaveHarness />, { withAuth: false });
-    fireEvent.click(screen.getByRole("button", { name: "Change type to Reactive" }));
+    fireEvent.click(screen.getByRole("button", { name: "Change type to Emergency" }));
     fireEvent.click(screen.getByRole("button", { name: "Save changes" }));
 
     expect(onSave).toHaveBeenCalledWith([
       { field: "severity", value: "2" },
       { field: "serviceId", value: "" },
+      { field: "workOrderType", value: "Emergency" },
+    ]);
+  });
+
+  it("preserves a compatible inactive service during a slide-over type change", () => {
+    const baseline = baseRow({ type: "PM", pm: "Historical service", serviceId: 702 });
+    const onSave = vi.fn();
+    const compatibleInactiveService = {
+      id: 702,
+      name: "Historical service",
+      trade: "Electrical",
+      iconKey: "wrench",
+      requiresCompletionDocument: false,
+      completionDocTemplate: null,
+      isActive: false,
+      supportedWorkOrderTypes: ["PM" as const, "Reactive" as const],
+    };
+
+    function SlideOverSaveHarness() {
+      const [draft, setDraft] = useState(baseline);
+      return (
+        <>
+          <SlideOverInfoTabEditView
+            draft={draft}
+            users={[]}
+            sites={[]}
+            vendors={[]}
+            pmTypes={[]}
+            services={[]}
+            serviceHistory={[compatibleInactiveService]}
+            allOrders={[]}
+            onDraftChange={(patch) => setDraft((current) => ({ ...current, ...patch }))}
+          />
+          <button
+            type="button"
+            onClick={() =>
+              onSave(expandTablePatchToBoardFieldOps(buildSlideOverPatch(draft, baseline)))
+            }
+          >
+            Save changes
+          </button>
+        </>
+      );
+    }
+
+    renderWithProviders(<SlideOverSaveHarness />, { withAuth: false });
+    fireEvent.click(screen.getByRole("button", { name: "Change type to Reactive" }));
+    fireEvent.click(screen.getByRole("button", { name: "Save changes" }));
+
+    expect(onSave).toHaveBeenCalledWith([
+      { field: "severity", value: "2" },
       { field: "workOrderType", value: "Reactive" },
     ]);
   });