When you make changes to your open graph actions, they will not be available to your end users until they are approved. This means your users will be able to use your "non-broken" actions, even if you make any breaking changes to them.
Another scenario (which is pretty obvious but I would still like to state):
If you have breaking changes in your application code that you dont want to deploy, you can create a staging environment and deploy your site there. So, for action approval you will submit staging server's address to facebook approval team. This will require that your staging server must have access to the app. This means your staging environment must be a sub domain of your production. Eg. lets say your production is www.example.com, then your staging should be staging.example.com.
Hope this helps.