What is the ruling on swearing to do something and then backing out of it due to parental intervention?

Obedience to parents is obligatory under specific conditions. When honoring an oath conflicts with obedience to parents, obedience to parents must take precedence, and one should break the oath while offering expiation, unless breaking it involves sin. This is supported by what Muslim narrated from Abu Hurayrah that the Messenger of Allah, peace and blessings be upon him, said: "Whoever takes an oath and then sees something better than it, let him do that (the better thing) and expiate for his oath." And what Al-Bukhari narrated from Abu Musa that the Prophet, peace and blessings be upon him, said: "By Allah, if Allah wills, I will not take an oath and then see something better than it, except that I will do that which is better and release myself from it (the oath)." So, if breaking the oath is better than persisting in it, then breaking it is recommended, and expiation becomes obligatory.