You remove or cut out those pipes and fit new ones.
This is done by plumbers or depending on the Pipe engineers.
Plumbers are people who earn a living dealing with pipes.
Plumbers
Plumbers
Oh the warp pipes there pipes because mario and luigi are plumbers
In the U.S. they are called plumbers, assuming you mean water pipes, and not the pipes that one smokes.
A Ranch
If you refer to the composition, it is Lead (Latin: Plumbum). "Roman roofs used lead in conduits and drain pipes and some were also covered with lead, lead was also used for piping and for making baths" -Wikipedia
They used Lead
Is the water still leaking? If so was the original line disconnected?
Most drain pipes are made of copper
lead