It is very difficult in New York State to be successful in a Court action to set aside an agreement for the reason that if it was easy to change separation agreements, people would not spend the time and the money to enter into them. This would then result in more litigation, which is not what the Courts want. Among factors that a Court will consider is whether or not an agreement is unconscionable or if one of the parties was unduly influenced. The standards are the same whether your agreement was reached in mediation or through attorney negotiation. If you mediate, however, whether or not a party has review attorneys while in and of itself is not determinative, it is a factor to be considered, especially in agreements drafted by a mediator attorney. So, it is recommended that couples have review attorneys.