I am not sure if this is the right place to post this question. I need to unsolder a DFN-8( package ) regulator from an board. After that I will have to solder another one, as I think it is not regulating at all. The board is already populated so put it back in a reflow machine is not a good idea. How I could remove the regulator without damaging other components. I have a hot air gun and hot plate....
You could try your heat gun. You'll have to pay attention to surrounding components. Also, if there's a pad underneath the device, that will make it a lot more difficult. I have used low temperature indium solder, e.g., "Chipquik", for removing QFPs with great success; not sure how that will work with a DFN package.
I would try with the hot air gun (I don't know if is the same as suggested by barry). It's not so difficult, just set the speed of the air not too high, athe temperature has to be quite high (usually I set the air to 550 degC) and operate on the component side. Move the tip all around the component to be unsoldered while holding it with tweezers to remove it when the tin is liquid enough. Do not keep the air flux fixed on a single point of the PCB in order not to damage it.
To protect the surrounding components you can place on them a strip of kapton.