How do I upgrade the Node runtime for an App Runner service?

I'm trying to change my service from running on the Nodejs 12 runtime to Nodejs 16. I'm not using Docker or an app runner configuration file.

When change the runtime dropdown and click Save, I get the following error:

Update service failed - invalid request
The runtime cannot be changed for a running service.

I've tried Pausing the service first - but then the Edit button for "Configure Build" becomes disabled.

Is it possible to upgrade the node runtime without deleting the service and starting over?