Can a party bring a motion to change if they simply disagree with the order, without any real change in circumstances?

No, not successfully — a motion to change is specifically built around showing that something material has genuinely changed since the existing order or agreement was made, not simply that one party has come to disagree with it, has found a new lawyer with a different view, or wishes the outcome had been different. Bringing a motion without a genuine change in circumstances is likely to be dismissed, and can also expose the party bringing it to a costs order for pursuing a motion with no real basis.

Courts generally protect the finality of existing orders and agreements deliberately, since allowing them to be revisited any time a party simply changes their mind would undermine the stability those orders are meant to provide, particularly for children whose lives are built around an existing parenting arrangement. A genuine change typically needs to be significant and something that wasn't accounted for, or reasonably foreseeable, when the original order was made. Anyone considering a motion to change should assess honestly, ideally with a lawyer, whether what's happened actually amounts to a material change.