Absolutely. With a joint legal custody order, you BOTH must mutually make decisions regarding the children's health, education and welfare, etc. Failing to do so can have severe consequences, including but not limited to your ex filing an OSC and requesting a change in custody.
Talk with your ex. If there is an agreement, get it in writing and signed by the Court (if possible) - you can do that via stipulation and order.
If she refuses and it is a true burden on you, you can file your OSC and request permission from the Court to change schools, but keep in mind that changing schools is oftentimes frowned upon by the Court because it disrupts the children's stability, social and peer groups, etc. and Courts sometimes may modify and/or change the visitation and/or custody orders to permit the child to stay in his or her school (with the other parent). There are a host of factors that the Court considers, but you MUST get your ex's permission prior to changing schools.
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Review your custody order, or judgment, carefully. Does it say that mutual agreement is required to change school enrollment? If so, then you're violating the order if you change the school enrollment without the agreement of your ex.
I suggest that you see if you can negotiate an AGREED change of school enrollment, in writing; otherwise, you may need to consult an experienced family law attorney and go back to court to make this happen.
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