a friend needs to get a re-fret on his 70's p-bass that he just acquired and someone told him they shave down the board and re-slot the newly planed fret board then put the frets in. so he is hesitant on doing it because he likes the sizes of the neck. i was always under the assumption that the frets just get banged out from the side, and then new frets are banged back in. or they get pulled out, and then new ones glued in. who is correct?