Why don't you just visit Twilight Sparkle or one of her friends, and ask them if they could write a letter to Princess Celestia, asking her to change the law?
AnonymousPrincess Celestia doesn’t just clap her hooves together and change a law on a whim; that’s something a dictator does. She oversees the law making process, but she lets greater Equestrian society handle the rest.
Ponyville is a pretty understanding society. There’s a decent chance it might pass here. But this would be a national law, since the current one in place is. It would have to be accepted across the entire country. Canterlot would probably be the single largest force to strike it down, but it wouldn’t be the only one.
Ponies are like any other creature. They’re very much set in their old ways. If there doesn’t appear to be a pressing need for change, it doesn’t happen.
