Heat might help. But you didn't answer the first question - why? Is there actually a problem with the existing wire, or are you rewiring on general principle? If the latter, don't. Unless you are playing CD4 records and the capacitance of the cables is an issue (and if it is, replacing the RCA cables is a better idea), usually there is no benefit, and the dangers of screwing things up is unpleasantly real, especially if you have to remove the pivot pins and then readjust them.
The geniuses on the internet who tell you you need to do this don't have to live with the consequences of a damaged or inoperable arm, but you might.
I've done it, and I heard no meaningful difference. I did it because I was putting two damaged arms together to make one good arm and I figured I might as well. I might as well not have.