I think that will be a little complicated. Lets say we do have the technology that is capable of something like that and the experts on that particular method manage to alter a former criminal's personality. But this means needing to delete his memories, alter his physical appearance and remove every information that can lead to his past just for this one person to start a new life. But what about other people that knew everything about him, should their memories be altered to? What about the criminal's relatives?
Aside from all those things I mentioned above, we also need to think of other possible issues. If there is a machine that can reset people, its not impossible to come up with another machine capable of reversing the process. And using that invention as a base for something else say... a device that can extract and translate memories into actual data. Imagine the harm a thing like that can be used for. So my answer is a NO to both the invention and messing with people's brains.