For numerous time it has happened that our DevOps guys have created a Azure WebApp with incorrect URL.
Which forced us the delete the resource group (as group contains web app, sql azure etc.) And re-create.
Is there a way to re-name /update the Web App URL via powershell Azure API or some hidden azure portal feature?
It's not possible to rename web apps.
And you don't need to delete the whole resource group. Just delete the one web app and recreate it with the correct name.