Plumber Job doesn't require ability to build

When a Developer gets to this, i found the "Empty Pipe" button. For anyone else who might see this afterwards, it's just another errand button down on the obttom -.- ... Devs, maybe add a tip in for that or an "Empty pipe" button when you click on the actual pipe like where it says deconstruct, disable autorepair, etc. or something to let people know, for this, and future additions. Anyway, i just got the game maybe 2 weeks ago and i love it so far (as did i with dont starve). keep the fun games cranking!

There was absolutely zero information provided about this. No idea how it works, guess I'm going to have to experiment.

What happens if I "empty" a pip that has water flowing through it. Can you only empty pipes with stationary contents?
If I decide to empty a pipe and then change my mind and pump liquid through it, will it work? be blocked? what happens?