A major update to the Visual Constructor is released on May 11th.
Was
You could not Edit API operations after the initial Save, only duplicate and edit a new one.
This was related to difficulty tracing where you use existing internal or external API operations, so if you changed it, you could have missed a place in your application to double-check if the logic of the edited Operation still fits.
Now
Since a search tool was released in Q1 of 2021, we can now ensure you will find every place in App, where you use the edited operation.
Now the platform allows editing and saving on any existing Operation.
As usual - Looking forward to your questions and comments in the Support channels.