Good evening, XXXXXXXX.
As for your question, it would depend on who's property the fence is on. If it's exactly on the property line, then each property owner should share responsibility. However, if it's on one side of the property line, even by a half-inch, then the responsibility falls on that property owner. Therefore, that person can decide whether or not he/she wants to fix the fence. If not, then you can't make him/her fix the fence. You can fix it, if you want, but you can't make the property owner fix it. Good luck.
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