How to change the floor plan?

Extreme example. Hamburg

Cost explosion at the Elbphilharmonie! Who is happy? The architect and the planning office, I think from the 20 million that were estimated, it became 70 million.

Or in our city! Stadium new construction, 1.7 million planned and approved in the layout, currently 3.2 million, justified by the higher fire protection requirements and the disability-compliant expansion including the elevator which is mandatory for new buildings.

Something has to happen, otherwise soon all construction sites will come to a halt.