Updated logic based on MR discussion

app/helpers/license_helper.rb

@@ -80,9 +80,8 @@ module LicenseHelper
     'https://about.gitlab.com/gitlab-com/'
   end
 
-  # Temporary Switch
   def show_promotions?
-    true
+     !License.current || (License.current&.trial? && license.expired?)
   end
 
   extend self

app/views/shared/promotions/_promote_servicedesk.html.haml

@@ -12,12 +12,12 @@
           Improve customer support with GitLab Service Desk.
       %p
         GitLab Service Desk is a simple way to allow people to create issues in your GitLab instance without needing their own user account. It provides a unique email address for end users to create issues in a project, and replies can be sent either through the GitLab interface or by email. End users will only see the thread through email.
-        %a{ href: 'https://docs.gitlab.com/ee/user/project/service_desk.html', target: '_blank' } Read more
+        %a{ href: '/help/user/project/service_desk.html', target: '_blank' } Read more
       - if current_user.admin?
         - if Gitlab.com?
           = link_to 'Upgrade your plan', upgrade_plan_url, class: 'btn btn-primary'
         - else
-          = link_to 'Start GitLab Enterprise Edition trial', new_trial_url, class: 'btn btn-primary'
+          = link_to License.current&.trial? && license.expired? ? 'Buy GitLab Enterprise Edition' : 'Start GitLab Enterprise Edition trial', new_trial_url, class: 'btn btn-primary'
       - else
         %p
           - if Gitlab.com?