My house wants to be remodeled. Can the sewers in the kitchen and bathroom be changed?

First of all, talk about the water supply and drainage pipes. The pipe used in the bathroom is De 1 10, and the kitchen only uses 75%. In addition, the floor drain and bathtub should be reopened, which affects the integrity of the floor.

Secondly, gas pipeline reconstruction is very troublesome.

The third is that the finished flue cannot be moved.