diff --git a/server/controllers/changeLocalName/details.test.ts b/server/controllers/changeLocalName/details.test.ts
index 304ae525..14d71373 100644
--- a/server/controllers/changeLocalName/details.test.ts
+++ b/server/controllers/changeLocalName/details.test.ts
@@ -74,6 +74,7 @@ describe('Change Local Name', () => {
     authService.getSystemClientToken = jest.fn().mockResolvedValue('token')
     locationsService.getLocation = jest.fn().mockResolvedValue(true)
     locationsService.updateLocalName = jest.fn().mockResolvedValue(true)
+    locationsService.getLocationByLocalName = jest.fn()
     analyticsService.sendEvent = jest.fn()
   })
 
@@ -119,8 +120,21 @@ describe('Change Local Name', () => {
     })
   })
 
+  it('sets the correct backLink and cancelLink in locals', () => {
+    const result = controller.locals(req, res)
+    expect(result.backLink).toBe('/view-and-update-locations/TST/e07effb3-905a-4f6b-acdc-fafbb43a1ee2')
+    expect(result.cancelLink).toBe('/view-and-update-locations/TST/e07effb3-905a-4f6b-acdc-fafbb43a1ee2')
+  })
+
+  it('sets the localName value from res if not in req', () => {
+    delete req.form.values.localName
+    res.locals.location.localName = 'Local Name from response'
+    const result = controller.locals(req, res)
+    expect(result.fields.localName.value).toBe('Local Name from response')
+  })
+
   describe('validateFields', () => {
-    it('if local name already exists, callback with error', async () => {
+    it('calls back with error if local name already exists', async () => {
       req.form.values.localName = 'existing local name'
       locationsService.getLocationByLocalName = jest.fn().mockResolvedValue(true)
 
@@ -133,12 +147,74 @@ describe('Change Local Name', () => {
 
       expect(callback).toHaveBeenCalledWith(expect.objectContaining({ localName: expectedError }))
     })
+
+    it('calls back with validation error if localName is null, ', async () => {
+      req.form.values.localName = ''
+      locationsService.getLocationByLocalName = jest.fn().mockResolvedValue(false)
+
+      const expectedError = controller.formError('localName', 'required')
+
+      const callback = jest.fn()
+      await controller.validateFields(req, res, callback)
+
+      await controller.saveValues(req, res, next)
+
+      expect(callback).toHaveBeenCalledWith(expect.objectContaining({ localName: expectedError }))
+    })
+  })
+
+  describe('errorCases', () => {
+    it('if errorCode is 101, callback', async () => {
+      req.form.values.localName = 'Local Name'
+      const errorsWith101 = new Error('Location not found')
+      locationsService.getLocationByLocalName = jest.fn().mockRejectedValue(errorsWith101)
+      const callback = jest.fn()
+
+      await controller.validateFields(req, res, callback)
+      expect(locationsService.getLocationByLocalName).toHaveBeenCalled()
+    })
+
+    it('if errorCode is not 101, callback', async () => {
+      req.form.values.localName = 'Local Name'
+      const genericError = new Error('Some other error')
+      locationsService.getLocationByLocalName = jest.fn().mockRejectedValue(genericError)
+      const callback = jest.fn()
+      await controller.validateFields(req, res, callback)
+      expect(locationsService.getLocationByLocalName).toHaveBeenCalled()
+    })
   })
 
   describe('saveValues', () => {
-    it('changes a local name via the locations API', async () => {
+    it('does not call locations API if localName is null ', async () => {
+      req.form.values.localName = ''
+      res.locals.location.localName = 'Wing A'
+      const callback = jest.fn()
+      await controller.validateFields(req, res, callback)
+      expect(locationsService.getLocationByLocalName).not.toHaveBeenCalled()
+      expect(locationsService.updateLocalName).not.toHaveBeenCalled()
+    })
+
+    it('does not call locations API if localName has not changed', async () => {
+      req.form.values.localName = 'Wing A'
+      res.locals.location.localName = 'Wing A'
+      const callback = jest.fn()
+      await controller.validateFields(req, res, callback)
+      expect(locationsService.getLocationByLocalName).not.toHaveBeenCalled()
+      expect(locationsService.updateLocalName).not.toHaveBeenCalled()
+    })
+
+    it('calls locations API if localName has been changed', async () => {
+      res.locals.location.localName = 'old Local Name'
       req.form.values.localName = 'changed local name'
+      const callback = jest.fn()
+      await controller.validateFields(req, res, callback)
       await controller.saveValues(req, res, next)
+      expect(locationsService.getLocationByLocalName).toHaveBeenCalledWith(
+        'token',
+        'TST',
+        'changed local name',
+        '57718979-573c-433a-9e51-2d83f887c11c',
+      )
       expect(locationsService.updateLocalName).toHaveBeenCalledWith(
         'token',
         'e07effb3-905a-4f6b-acdc-fafbb43a1ee2',
@@ -147,6 +223,27 @@ describe('Change Local Name', () => {
       )
     })
 
+    it('sanitizes localName before calling locations API', async () => {
+      req.form.values.localName = '  <br> Sanitized Wing Name </br>  '
+      const callback = jest.fn()
+      await controller.validateFields(req, res, callback)
+      await controller.saveValues(req, res, next)
+      expect(locationsService.getLocationByLocalName).toHaveBeenCalledWith(
+        'token',
+        'TST',
+        'Sanitized Wing Name',
+        '57718979-573c-433a-9e51-2d83f887c11c',
+      )
+      expect(locationsService.updateLocalName).toHaveBeenCalledWith(
+        'token',
+        res.locals.location.id,
+        'Sanitized Wing Name',
+        res.locals.user.username,
+      )
+
+      expect(next).toHaveBeenCalled()
+    })
+
     it('sends an analytics event', async () => {
       await controller.saveValues(req, res, next)
 
diff --git a/server/controllers/changeLocalName/details.ts b/server/controllers/changeLocalName/details.ts
index b6086db0..1febf00e 100644
--- a/server/controllers/changeLocalName/details.ts
+++ b/server/controllers/changeLocalName/details.ts
@@ -40,6 +40,9 @@ export default class Details extends FormInitialStep {
 
       const validationErrors: any = {}
 
+      if (!sanitizedLocalName) {
+        return callback({ ...errors, ...validationErrors })
+      }
       if (sanitizeString(String(values.localName)) === sanitizeString(res.locals.location.localName)) {
         return res.redirect(`/view-and-update-locations/${prisonId}/${locationId}`)
       }