Azure web app won't change from Basic: 1 Small to Free or Shared pricing tier

You must turn off the "Always On" feature of the Web App from the Azure portal "Application Settings" before changing (downgrading) the App Service Plan.

So the new portal has a few bugs. I tried to do this operation with the old portal and got a helpful error message:

Cannot update the site 'test' because it uses x64 worker process which is not allowed in the target compute mode.

If you choose a setting not available in a downgrade, for example 64-bit or "Always On" (confirmed), and then try to downgrade, it will say it succeeded when actually it failed.

And they won't let us use the old portal soon. Great.

"Always On" can be found here now: