apps:rename <old-app> <new-app>

dokku apps:rename node-js-app io-js-app

-----> Creating io-js-app... done
Destroying node-js-app (including all add-ons)
       Unlinking from railsdatabase
App node-js-app has not been deployed
-----> Cleaning up...
-----> Cleaning up...
Renaming node-js-app to io-js-app... done