I think it is best if you consult a plumber. You might ask why. Here are some reasons why you should leave it to the professionals:
-Even if you had managed to successfully complete a bathroom operation and it works smoothly for a few months, some damages only show up after some time when it is all too late.
-There could be problems already existing, extending it can only further cause damage and that means additional expenses.
-The most important factor is that hiring a plumbing consultant saves your money and time.