The cheat codes described above are a good quick fix if you don't want to bother doing it in-game.
The in-game way to repeal the NAP is to click the mailbox and select "repeal neighborhood action plan". You then have to get 5 signatures from other sims in your neighborhood who also want to repeal the NAP. You can even have a NAP repeal party on the weekend if you want. It's still a cinch compared to RL activism ;) And if you do remember to vote during the next voting period, it's stupidly easy to get whatever NAP you want enacted, as you probably have gained enough influence through gameplay to outvote all the townies put together.