diff --git a/src/kdbusservice.h b/src/kdbusservice.h
--- a/src/kdbusservice.h
+++ b/src/kdbusservice.h
@@ -115,7 +115,14 @@
          * The exit value of a @c Unique instance can be set from the running
          * instance with setExitValue(), the default value is @c 0.
          */
-        NoExitOnFailure = 4
+        NoExitOnFailure = 4,
+        /**
+         * Indicates that if there's already a unique service running, to be quit and replaced
+         * with our own.
+         *
+         * @since 5.62
+         */
+        Replace = 8
     };
     Q_ENUM(StartupOption)
 
diff --git a/src/kdbusservice.cpp b/src/kdbusservice.cpp
--- a/src/kdbusservice.cpp
+++ b/src/kdbusservice.cpp
@@ -74,7 +74,7 @@
     int exitValue;
 };
 
-KDBusService::KDBusService(StartupOptions options, QObject *parent)
+KDBusService::KDBusService(KDBusService::StartupOptions options, QObject* parent)
     : QObject(parent), d(new KDBusServicePrivate)
 {
     new KDBusServiceAdaptor(this);
@@ -106,6 +106,20 @@
             }
         }
 
+        if (options & Replace) {
+            auto message = QDBusMessage::createMethodCall(d->serviceName,
+                                                      QStringLiteral("/MainApplication"),
+                                                      QStringLiteral("org.qtproject.Qt.QCoreApplication"),
+                                                      QStringLiteral("quit"));
+
+            auto replyMessage = QDBusConnection::sessionBus().call(message);
+            if (replyMessage.type() == QDBusMessage::ErrorMessage) {
+                qCritical() << "failed to quit service" << d->serviceName << replyMessage;
+            } else while (QDBusConnection::sessionBus().interface()->isServiceRegistered(d->serviceName)) {
+                QCoreApplication::processEvents(QEventLoop::AllEvents);
+            }
+        }
+
         QDBusConnection::sessionBus().registerObject(QStringLiteral("/MainApplication"), QCoreApplication::instance(),
                 QDBusConnection::ExportAllSlots |
                 QDBusConnection::ExportScriptableProperties |