diff --git a/src/kdbusservice.h b/src/kdbusservice.h
--- a/src/kdbusservice.h
+++ b/src/kdbusservice.h
@@ -115,7 +115,17 @@
          * 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.
+         *
+         * If exported, it will try first quitting the service calling org.qtproject.Qt.QCoreApplication.quit,
+         * which is exported by @class KDBusService by default.
+         *
+         * @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
@@ -168,7 +168,32 @@
 
         auto queueOption = QDBusConnectionInterface::DontQueueService;
 
-        if (options & KDBusService::Unique) {
+        if (options & KDBusService::Replace && QDBusConnection::sessionBus().interface()->isServiceRegistered(d->serviceName)) {
+            auto message = QDBusMessage::createMethodCall(d->serviceName,
+                                                      QStringLiteral("/MainApplication"),
+                                                      QStringLiteral("org.qtproject.Qt.QCoreApplication"),
+                                                      QStringLiteral("quit"));
+            auto reply = QDBusConnection::sessionBus().call(message); //deliberately block until it's done, so we register the name after the app quits
+
+            //Give a grace time to the original instance
+            {
+                QEventLoop unregistrationLoop;
+                connect(bus, &QDBusConnectionInterface::serviceUnregistered,
+                        this, [&unregistrationLoop, this](const QString &service) {
+                    if (service != d->serviceName) {
+                        return;
+                    }
+
+                    unregistrationLoop.quit();
+                });
+
+                QTimer quitTimer;
+                quitTimer.start(2000);
+                connect(&quitTimer, &QTimer::timeout, &unregistrationLoop, &QEventLoop::quit);
+                unregistrationLoop.exec();
+            }
+            queueOption = QDBusConnectionInterface::ReplaceExistingService;
+        } else if (options & KDBusService::Unique) {
             // When a process crashes and gets auto-restarted by KCrash we may
             // be in this code path "too early". There is a bit of a delay
             // between the restart and the previous process dropping off of the