diff --git a/internal/cmd/initcmd/init.go b/internal/cmd/initcmd/init.go
index 04fba2e..0d7143c 100644
--- a/internal/cmd/initcmd/init.go
+++ b/internal/cmd/initcmd/init.go
@@ -72,6 +72,7 @@ func run(command *cobra.Command, dependencies Dependencies, flags Setup, nonInte
 	if err != nil {
 		return exitcode.New(exitcode.Config, err)
 	}
+	configuredBackend := strings.TrimSpace(configValue.Keyring.Backend)
 	setup := Setup{
 		ClientID: configValue.ClientID, RedirectURI: configValue.RedirectURI,
 		CredentialRef: configValue.CredentialRef, Backend: configValue.Keyring.Backend,
@@ -89,11 +90,12 @@ func run(command *cobra.Command, dependencies Dependencies, flags Setup, nonInte
 	backendSet := backendFlag != nil && backendFlag.Changed
 	runtimeBackend := pointerValue(dependencies.Backend)
 	runtimeBackendSet := backendSet
+	interactive := dependencies.Interactive && !nonInteractive
 	if backendSet {
 		setup.Backend = runtimeBackend
 	}
 
-	if dependencies.Interactive && !nonInteractive {
+	if interactive {
 		prompt := dependencies.Prompt
 		if prompt == nil {
 			prompt = func(value *Setup) error { return RunPrompt(command.InOrStdin(), command.ErrOrStderr(), value) }
@@ -127,7 +129,7 @@ func run(command *cobra.Command, dependencies Dependencies, flags Setup, nonInte
 
 	result, err := dependencies.Initializer.Initialize(command.Context(), InitializeOptions{
 		Config: configValue, Profile: profile, Backend: runtimeBackend, BackendSet: runtimeBackendSet,
-		Overwrite: overwrite, Verify: !noVerify,
+		Overwrite: overwrite || (interactive && strings.TrimSpace(setup.Backend) != configuredBackend), Verify: !noVerify,
 		Authorization: auth.Request{
 			ClientID: configValue.ClientID, RedirectURI: configValue.RedirectURI,
 			NoBrowser: noBrowser || authCodeStdin, AuthCodeStdin: authCodeStdin,
diff --git a/internal/cmd/initcmd/init_test.go b/internal/cmd/initcmd/init_test.go
index 7146608..9df7984 100644
--- a/internal/cmd/initcmd/init_test.go
+++ b/internal/cmd/initcmd/init_test.go
@@ -120,6 +120,43 @@ func TestInteractiveInitUsesPromptedBackendForStoreAndConfig(t *testing.T) {
 	}
 }
 
+func TestInteractiveInitBackendChangeReplacesDestinationCredential(t *testing.T) {
+	harness := newInitHarness(t)
+	cfg := config.Default()
+	cfg.Keyring.Backend = "file"
+	if err := config.Save(harness.scope, cfg); err != nil {
+		t.Fatal(err)
+	}
+	key := "default/" + credentials.OAuthTokenKey
+	harness.store.values[key] = "stale-destination-credential"
+	harness.interactive = true
+	harness.prompt = func(setup *Setup) error {
+		setup.ClientID = "client-id"
+		setup.Backend = "keychain"
+		return nil
+	}
+	if err := harness.execute("--no-verify"); err != nil {
+		t.Fatal(err)
+	}
+	if harness.store.values[key] == "stale-destination-credential" || harness.store.setCalls != 1 {
+		t.Fatalf("credential = %q, set calls = %d", harness.store.values[key], harness.store.setCalls)
+	}
+}
+
+func TestNonInteractiveInitBackendChangeStillRequiresOverwrite(t *testing.T) {
+	harness := newInitHarness(t)
+	cfg := config.Default()
+	cfg.Keyring.Backend = "file"
+	if err := config.Save(harness.scope, cfg); err != nil {
+		t.Fatal(err)
+	}
+	harness.store.values["default/"+credentials.OAuthTokenKey] = "old-secret"
+	err := harness.execute("--backend", "keychain", "--non-interactive", "--client-id", "client-id", "--no-verify")
+	if !errors.Is(err, credstore.ErrExists) {
+		t.Fatalf("error = %v", err)
+	}
+}
+
 func TestNonInteractiveInitNamesMissingClientID(t *testing.T) {
 	harness := newInitHarness(t)
 	called := false