diff --git a/public/locales/de-DE/translation.json b/public/locales/de-DE/translation.json
index 5f7d6a9..a072fe5 100644
--- a/public/locales/de-DE/translation.json
+++ b/public/locales/de-DE/translation.json
@@ -370,6 +370,9 @@
       "startableInTasklist": "startableInTasklist"
     },
     "instance": {
+      "activate": "Instanz aktivieren",
+      "suspend": "Instanz anhalten",
+      "suspension-success": "Prozessinstanz-Status aktualisiert.",
       "sort": {
         "startTime": "Startzeit",
         "instanceId": "Instanz-ID",
diff --git a/public/locales/en-US/translation.json b/public/locales/en-US/translation.json
index ac20fbe..32c133e 100644
--- a/public/locales/en-US/translation.json
+++ b/public/locales/en-US/translation.json
@@ -370,6 +370,9 @@
       "startableInTasklist": "startableInTasklist"
     },
     "instance": {
+      "activate": "Activate Instance",
+      "suspend": "Suspend Instance",
+      "suspension-success": "Process instance state updated.",
       "sort": {
         "startTime": "Start time",
         "instanceId": "Instance ID",
diff --git a/src/api/resources/process_instance.js b/src/api/resources/process_instance.js
index d1d6c02..86b0136 100644
--- a/src/api/resources/process_instance.js
+++ b/src/api/resources/process_instance.js
@@ -1,4 +1,4 @@
-import { GET, POST } from "../helper.jsx";
+import { GET, POST, PUT } from "../helper.jsx";
 
 const get_process_instance = (state, instance_id) =>
   GET(
@@ -33,6 +33,14 @@ const get_process_instance_variables = (state, instance_id) =>
     state.api.process.instance.variables,
   );
 
+const set_process_instance_suspension_state = (state, instance_id, suspended) =>
+  PUT(
+    `/process-instance/${instance_id}/suspended`,
+    { suspended },
+    state,
+    state.api.process.instance.suspension,
+  );
+
 const get_called_process_instances = (state, instance_id) =>
   GET(
     `/process-instance?superProcessInstance=${instance_id}`,
@@ -105,6 +113,10 @@ const modify_process_instance_async = (
 const process_instance = {
   one: get_process_instance,
   variables: get_process_instance_variables,
+  activate: (state, instance_id) =>
+    set_process_instance_suspension_state(state, instance_id, false),
+  suspend: (state, instance_id) =>
+    set_process_instance_suspension_state(state, instance_id, true),
   called: get_called_process_instances,
   count: get_process_instance_count,
   all: get_all_process_instances,
diff --git a/src/api/resources/process_instance.test.js b/src/api/resources/process_instance.test.js
index 90bb054..ff4d231 100644
--- a/src/api/resources/process_instance.test.js
+++ b/src/api/resources/process_instance.test.js
@@ -3,9 +3,10 @@ import { describe, it, vi, beforeEach } from "vitest";
 vi.mock("../helper.jsx", () => ({
   GET: vi.fn(),
   POST: vi.fn(),
+  PUT: vi.fn(),
 }));
 
-import { GET, POST } from "../helper.jsx";
+import { GET, POST, PUT } from "../helper.jsx";
 import { create_mock_state, expect_api_call } from "../../test/helpers.js";
 import process_instance from "./process_instance.js";
 
@@ -33,6 +34,26 @@ describe("api/resources/process_instance", () => {
     });
   });
 
+  it("suspend() PUTs a suspended process instance state", () => {
+    process_instance.suspend(state, "inst-1");
+    expect_api_call(PUT, {
+      url: "/process-instance/inst-1/suspended",
+      body: { suspended: true },
+      state,
+      signal: state.api.process.instance.suspension,
+    });
+  });
+
+  it("activate() PUTs an active process instance state", () => {
+    process_instance.activate(state, "inst-1");
+    expect_api_call(PUT, {
+      url: "/process-instance/inst-1/suspended",
+      body: { suspended: false },
+      state,
+      signal: state.api.process.instance.suspension,
+    });
+  });
+
   it("called() GETs sub process instances by superProcessInstance", () => {
     process_instance.called(state, "inst-1");
     expect_api_call(GET, {
diff --git a/src/pages/Processes.jsx b/src/pages/Processes.jsx
index d6ac79e..38be567 100644
--- a/src/pages/Processes.jsx
+++ b/src/pages/Processes.jsx
@@ -686,7 +686,7 @@ const DefinitionsEmpty = () => {
       <a
         href="https://docs.operaton.org/manual/latest/installation/full/tomcat/manual/"
         target="_blank"
-        rel="noopener"
+        rel="noreferrer"
       >
         {t("processes.empty.how-to")}
       </a>
@@ -928,8 +928,7 @@ const InstanceDetails = () => {
       params: { selection_id, definition_id, panel },
       query,
     } = useRoute(),
-    history_mode = query.history === "true",
-    [t] = useTranslation();
+    history_mode = query.history === "true";
 
   if (selection_id) {
     if (
@@ -965,21 +964,67 @@ const InstanceDetails = () => {
 const InstanceDetailsDescription = () => {
   const state = useContext(AppState),
     [t] = useTranslation(),
+    { query } = useRoute(),
+    history_mode = query.history === "true",
     data = state.api.process.instance.one.value?.data;
+  const set_suspension_state = (suspended) => {
+    if (!data?.id) return;
+    const action = suspended ? "suspend" : "activate";
+    void Promise.resolve(engine_rest.process_instance[action](state, data.id)).then(
+      () => engine_rest.process_instance.one(state, data.id),
+    );
+  };
 
   return (
-    <dl>
-      <dt>{t("processes.instance-id")}</dt>
-      <dd
-        class="font-mono copy-on-click"
-        onClick={copyToClipboard}
-        title={t("processes.click-to-copy")}
-      >
-        {data?.id ?? "—"}
-      </dd>
-      <dt>{t("processes.business-key")}</dt>
-      <dd>{data?.businessKey ?? "—"}</dd>
-    </dl>
+    <>
+      <RequestState
+        signal={state.api.process.instance.suspension}
+        on_nothing={() => null}
+        on_success={() => (
+          <p class="success">{t("processes.instance.suspension-success")}</p>
+        )}
+      />
+      <dl>
+        <dt>{t("processes.instance-id")}</dt>
+        <dd
+          class="font-mono copy-on-click"
+          onClick={copyToClipboard}
+          title={t("processes.click-to-copy")}
+        >
+          {data?.id ?? "—"}
+        </dd>
+        <dt>{t("processes.business-key")}</dt>
+        <dd>{data?.businessKey ?? "—"}</dd>
+        <dt>{t("common.state")}</dt>
+        <dd>
+          {data?.suspended === true
+            ? t("common.suspended")
+            : data?.suspended === false
+              ? t("common.active")
+              : "—"}
+        </dd>
+      </dl>
+      {!history_mode && data?.id ? (
+        <div class="button-group">
+          {data.suspended ? (
+            <button
+              type="button"
+              onClick={() => set_suspension_state(false)}
+            >
+              {t("processes.instance.activate")}
+            </button>
+          ) : (
+            <button
+              type="button"
+              class="secondary"
+              onClick={() => set_suspension_state(true)}
+            >
+              {t("processes.instance.suspend")}
+            </button>
+          )}
+        </div>
+      ) : null}
+    </>
   );
 };
 
@@ -1043,20 +1088,16 @@ const InstanceVariables = () => {
             ? !history_mode
               ? Object.entries(
                   state.api.process.instance.variables.value.data,
-                ).map(
-                  // eslint-disable-next-line react/jsx-key
-                  ([name, { type, value }]) => (
-                    <tr>
-                      <td>{name}</td>
-                      <td>{type}</td>
-                      <td>{value}</td>
-                    </tr>
-                  ),
-                )
+                ).map(([name, { type, value }]) => (
+                  <tr key={name}>
+                    <td>{name}</td>
+                    <td>{type}</td>
+                    <td>{value}</td>
+                  </tr>
+                ))
               : state.api.process.instance.variables.value.data.map(
-                  // eslint-disable-next-line react/jsx-key
                   ({ name, type, value }) => (
-                    <tr>
+                    <tr key={name}>
                       <td>{name}</td>
                       <td>{type}</td>
                       <td>{value}</td>
@@ -1464,13 +1505,6 @@ const JobDefinitions = () => {
   );
 };
 
-const BackToListBtn = ({ url, title, className }) => (
-  <a className={`tabs-back ${className || ""}`} href={url} title={title}>
-    <Icons.arrow_left />
-    <Icons.list />
-  </a>
-);
-
 const DefinitionsManage = () => {
   const state = useContext(AppState),
     { route } = useLocation(),
diff --git a/src/pages/Processes.test.jsx b/src/pages/Processes.test.jsx
index 60c4b48..0222d7f 100644
--- a/src/pages/Processes.test.jsx
+++ b/src/pages/Processes.test.jsx
@@ -389,6 +389,79 @@ describe("ProcessesPage — instance details", () => {
     expect(getByText("BK-9")).toBeTruthy();
   });
 
+  it("suspends a live process instance", async () => {
+    mockParams = {
+      definition_id: "proc:1",
+      panel: "instances",
+      selection_id: "inst-9999",
+      sub_panel: "vars",
+    };
+    signal_response(state.api.process.instance.one, {
+      id: "inst-9999",
+      businessKey: "BK-9",
+      suspended: false,
+    });
+    const { getByText } = renderPage(state);
+
+    fireEvent.click(getByText("processes.instance.suspend"));
+    await Promise.resolve();
+    await Promise.resolve();
+
+    expect(engine_rest.process_instance.suspend).toHaveBeenCalled();
+    expect(engine_rest.process_instance.suspend.mock.lastCall[0]).toBe(state);
+    expect(engine_rest.process_instance.suspend.mock.lastCall[1]).toBe(
+      "inst-9999",
+    );
+    expect(engine_rest.process_instance.one.mock.lastCall[0]).toBe(state);
+    expect(engine_rest.process_instance.one.mock.lastCall[1]).toBe("inst-9999");
+  });
+
+  it("activates a suspended live process instance", async () => {
+    mockParams = {
+      definition_id: "proc:1",
+      panel: "instances",
+      selection_id: "inst-9999",
+      sub_panel: "vars",
+    };
+    signal_response(state.api.process.instance.one, {
+      id: "inst-9999",
+      businessKey: "BK-9",
+      suspended: true,
+    });
+    const { getByText } = renderPage(state);
+
+    fireEvent.click(getByText("processes.instance.activate"));
+    await Promise.resolve();
+    await Promise.resolve();
+
+    expect(engine_rest.process_instance.activate).toHaveBeenCalled();
+    expect(engine_rest.process_instance.activate.mock.lastCall[0]).toBe(state);
+    expect(engine_rest.process_instance.activate.mock.lastCall[1]).toBe(
+      "inst-9999",
+    );
+    expect(engine_rest.process_instance.one.mock.lastCall[0]).toBe(state);
+    expect(engine_rest.process_instance.one.mock.lastCall[1]).toBe("inst-9999");
+  });
+
+  it("keeps historic process instance details read-only", () => {
+    mockParams = {
+      definition_id: "proc:1",
+      panel: "instances",
+      selection_id: "inst-9999",
+      sub_panel: "vars",
+    };
+    mockQuery = { history: "true" };
+    signal_response(state.api.process.instance.one, {
+      id: "inst-9999",
+      businessKey: "BK-9",
+      suspended: false,
+    });
+    const { queryByText } = renderPage(state);
+
+    expect(queryByText("processes.instance.suspend")).toBeNull();
+    expect(queryByText("processes.instance.activate")).toBeNull();
+  });
+
   it("variables sub-panel fetches and renders live variables", () => {
     mockParams = {
       definition_id: "proc:1",
diff --git a/src/state.js b/src/state.js
index f63ad2e..820797f 100644
--- a/src/state.js
+++ b/src/state.js
@@ -119,6 +119,7 @@ const createAppState = () => {
         list: signal(null),
         count: signal(null),
         variables: signal(null),
+        suspension: signal(null),
         by_defintion_id: signal(null),
         activity_instances: signal(null),
         modification: signal(null),