1, I wonder what is the structure of your house? If it is a concrete frame, look at the wall material near the sewer pipe. If it is a infilled wall, you can buy two elbows to replace the pipe from the wall. If it is brick and concrete, it will not work;

2. If you don't know if there is any property in your community after receiving the external wall, generally speaking, property is not allowed, which will affect the overall beauty of the facade of the house, but it is not absolutely impossible to change it like this. The reconstructed pipeline should be wrapped with an insulation layer, which is spongy in the market, and a layer of sun-proof reflective paper should be wrapped outside the insulation layer to prevent the pipeline from deformation and aging caused by temperature change and sunlight;

3. It is not recommended to thin the pipes in the bathroom, because the dirt in the bathroom is large, and it is easy to block the pipes when they are thin. You can also consider improving the pipeline in the wall.

4. The kitchen is connected with smoke exhaust pipes and sanitary indirect ventilation pipes, but attention should be paid to the sealing of flue and ventilation pipes.