grade 2 listed building

[neald]

hello everybody,i am doing some work on a grade 2 listed farmhouse,i will have to reove an old cast iron drainpipe and hopper so i can repair the wall behind it as there's water marks on the walls inside the house,first thing is how to remove the old pipe?i know it will be damaged when removing it so what can i use in it's place bearing in mind it's a listed building?..thanks neil