I'm no expert on barometers but, as they measure atmospheric pressure, I would assume it doesn't need re-setting if it was measuring the correct pressure before it was moved, then it should still measure the correct pressure wherever it it's located.
However, if it isn't measuring the correct pressure now, you need to find out what the atmospheric pressure is - try a local weather forecast website - then adjust the little screw that's usually on the back so your needle is reading the correct pressure.